Since I saw this thread referenced in one of the other more recent threads.
AUSTRALIA 1995 - Big Day Out 2005 - Taste of Chaos 2006, 2007 - Gigantour 2007, 2008, 2009, 2011 - Soundwave
Europe 2004 - Sweden Rocks 2004 - Rockwave Greece 2004 - Bang Your Head Germany
Open Seas 2011 - 70,000 Tons of Metal
As this is a thread about reviews, my quick abridged thoughts on the above.
Big Day Out - well organised festival, that doesn't appeal to my tastes much anymore. 1995 was a blast though - Silverchair were still a bunch of kids but they had just hit it big here. I can still remember Johns being overawed by the size of the crowd there to see them play. He nervously addressed the crowd with something like "you guys do know that Screaming Trees are playing on the main stage, and...they're really good!"
Taste of Chaos - crap music.
Gigantour - Great great great. Hope it comes back. Getting to see Dave and Cristina sing A Tout Le Monde was worth the price of admission
Soundwave - I don't know why I keep going back, its always so BADLY organised....actually I do know why I keep going back. This festival satisfies my diverse music tastes more than any other. Fave memory would be getting to meet Marta from Bleeding Through (such a sweetheart). Cannot wait for the 2011 one - lineup is epic!!
European festivals - loved them all! Cannot say any more than that - the diversity of Sweden Rocks was fantastic. The fact that BYH only has the one stage was quite cool too - sucked if a band you didn't like was playing I guess, but there are plenty of other things to do.
All the Noctis fests (Calgary) have been fantastic,they always have at least 2 awesome international bands that I enjoy, a load of great local acts and I usually find myself surprised by more than one other band. Noctis 2010 was probably the best so far, for many reasons. Metsatoll, Manegarm, Striker, Viathyn, Root, Sodom, Midnight and many other killer bands plus a load of great speakers at the conference.
I Really enjoyed Wacken. I think everyone should go once, because it's a really crazy experience, and I'm glad I went. Met some amazing people, saw some fantastic bands and it's a wild way to break into the festival atmosphere. I dunno if I'd go again, it'd have to be an amazing lineup. There are too many other fests I want to see. Wacken is also extremely well-organized, it runs like a machine.
Bloodstock (UK) was good. The lineup kicked ass, it was a bit smaller, but the organization wasn't nearly as good and it was expensive as fuck. There must have been 10,000 people there and they seemed to have prepared for 3,000. But it was nice being around people only speaking English and I made some lasting friendships. I'd go again, so long as the lineup was stellar.
Fests I want to attend:
Metalcamp Slovenia Keep it True (Germany) Up the Hammers (Greece) Hammer of Doom (Germany) Headbangers Open Air (Germany) Ragnarök Festival (Germany) ProgPower (USA) Metal Merchants Festival (Norway)
[+] GODS OF METAL, Italy in 2001, 2002, 2003, 2004, 2005, 2006 and 2007: it was a great festival with excellent lineups but the festival organization was sometimes... very haphazardly, don't know if it's the right word in english And I say it "was" because I think that the festival lineups are not so good now and plus, since 2008 the festival take place at the same week-end than other better festivals (until 2007 it took place the first week-end of june and there was no real concurrency). GODS OF METAL 2005 was for me the best.
[+] WACKEN, Germany in 2002, 2003, 2004, 2006, 2007, 2008, 2009 and 2010: WACKEN was for me THE festival to be! Excellent lineups, excellent atmosphere, ... But since 2007 it has become too big. In 2004 we were 40,000 people I think, 60,000 in 2006 and in 2008... 70,000! It's too much, they should have limited the number of persons. And the lineups are not so good these last times or there are some weird choices like a fucking country band on the main stage (no kidding!) playing one hour while LIZZY BORDEN was on the smallest stage under a tent playing... half an hour WACKEN 2002 was for me the best (apocalyptic weather conditions the first day haha!)
[+] HELLFEST, France in 2008, 2009 and 2010: In my opinion it's today one of the best metal festival in the world and I don't write that because it takes place in France. Lineups are excellent and very varied, since 2008 it's very well organized, ... It's incredible to have such a festival in France, organizers had to fight to succeed!
[+] GRASPOP METAL MEETING, Belgium in 2004, 2006, 2007, 2008 and 2009: excellent lineups, very well organized, belgium beers are the best but... it's the only festival where I was in trouble several times. Sorry for the flemish people but I have the feeling that there are too much "relationship" problems between us (french people or french speaking people) and you :/
[+] DYNAMO, Netherlands in 2002 and 2005: it was such a big festival in the 90's but several cancellations in the 2000's have killed this festival
[+] BANG YOUR HEAD, Germany in 2003 and 2010: very good human scaled festival. Too bad it took place the same week-end than other big festivals but since 2010 it takes place in july with no too much concurrency so it's perfect!
[+] EARTHSHAKER, Germany in 2005 and 2006: it was a quite good festival! I'm a huge fan of ManOwaR so in 2005 it was something incredible for me! But competition with other festivals has become fierce and killed this one.
[+] ROTONDE FESTIVAL, France in 2003, 2004 and 2005: it was a small, not very well organized but very nice festival. But it was very hard to succeed with a heavy metal festival in France before the perseverance of the HELLFEST's organizers
Some other summer festivals I've seen: WÂLDROCK, Netherlands in 2004, FIELDS OF ROCK, Netherlands in 2007 (excellent festival but also killed by concurrency), MAGIC CIRCLE FESTIVAL, Germany in 2007 and 2008 (as a huge fan of ManOwaR it was the place to be! The first year the ticket cost was 10€ a day! In 2008 most of the beer was free! And ManOwaR played incredible gigs with their 6 first full albums on stage!), SONISPHERE, Poland in 2010, SONISPHERE, Romania in 2010, DOWNLOAD FESTIVAL, UK in 2010 (but just one day to see AC/DC gig), ROCK HARD FESTIVAL, Germany in 2010 (another quite good human scaled festival)
:edit: sorry for the mistakes in my sentences, I still need to practice my english
Wacken Open Air: 2007, 2008, 2009, 2010 (and again in 2011) It’s become a tradition for my friends and me to attend Wacken. We always have a camp with about 30 Danes and that’s the main reason I’m going there again this year. The festival has become too mainstream and commercial like others say, and the line-up could be much better every year. But I always meet some great people in the camping area so its mainly because of what happens in the camping area I keep returning.
Brutal Assault: 2008, 2010 Brutal Assault on the other hand has had an awesome line-up both years I’ve been there. A big plus is that a beer only costs one euro. The only problem with this festival is that its only young people in the Czech Republic who understands English so it’s a bit difficult to communicate with the natives.
Royal Metal Fest: 2008, 2009, 2010 (and again in 2011) Royal Metal Fest is the best Danish metal festival there is. Its an indoors festival and its located in the middle of the second largest city in Denmark. There are a lot of pubs nearby where you often meet the bands from the festival. There can only be around 700-800 people at the festival, but there is always a great atmosphere.
"Vi kæmper kun for øl Vi kæmper kun for øl Vi kæmper kun for øl og for penge Og hvis vi ingen penge får Og ingen øl ligeså Så må i kæmpe kampen uden os!" Skål!
Wacken Open Air, Germany [1999-2010 except 2009] (pic from 2000)
It was nice until it got overcrowded... when 4 stages were side by side in pairs and only 2 bands performed at the same time. Now it just to big, but I still go there cause I got used to goin' every year.
Bang Your Head, Germany [2001-2008] (pic from 2006; Death Angel)
I like a few things about this festival: the festival area is on tarmac, so there is no mud in case of rain... and there is only one stage, so you don't need to run from one side of the area to another like crazy.
Metalfest Vienna  Sodom: Rock The Nation "renamed" the festival and moved it to Slovenia... it became Metalcamp in 2004
Metal Mania Open Air, Slovenia [2002-2003, 2005-2008] A small (up to 1300 people) festival with mostly local bands and a few foreign ones. Great atmosphere, crazy (and mostly totally drunk) crowd! I worked as a stage manager in 2003, as booking agent/stage manager from 2005-2008...
Metal Dose Festival, Slovenia  There was no Metal Mania Open Air that year, so another small festival was organized in Slovenia... and it was a complete failure.
Metalcamp, Slovenia [2004, 200?, 200?, 200? - Nuux, help me out with the last 2-3?] It's nice but I didn't manage to go every year - it just didn't work out time wise
Masters Of Rock, Czech Republic [2004-2007] (pic from 2005; Rage)
In 2004 the festival was quite small with nice relaxation area in the woods where the beer was brought to you for less than 1€... oh, good old times. The festival got bigger every year and the organizers didn't keep up with the growth (not enough thrash bins, toilets, ...).
Gods Of Metal, Italy [2004-2005] (pic from 2005; Obituary)
Great bands, 5 toilets for 50.000 people, gravel "camping area", expensive beer, no shadow... did I mention great bands yet?
Earthshaker, Germany  Destruction: Also known as Gayowar festival...
Paranoid Open Air, Slovenia [2009, 2010 as Paranoid Picnic Open Air] Candlemass: A festival I co-organized from start to end (booking, running order, promotion, contracts, permits, ...) We had 36 bands in 3 days... including Obscura, Atheist, Candlemass, Psycroptic, Theatres Des Vampires, Beneath The Massacre, Misery Index, Hate Eternal, Blaze Bayley, Ram, Necronomicon, Agnostic Front, Onslaught, Taake, ...
Great festival according to the bands and visitors...but a financial disaster In 2010 we organized a small picnic with 6 bands playing instead and it was great...so we'll do it again this year.
Metalway Festival, Spain  Strange festival (2 weekends with nothing to do in between - we drove to the seaside during that time...extra ~500 miles on top of already quite a distance - 1100 miles one way)... none there spoke English, the crowd was really small considering the billing they had. No wonder there was nothing goin' on there in 2010.
I probably forgot some small festivals, but I think I got the big ones covered.
And now... (drum roll) ... 70000 TONS OF METAAAAAAAAAAAAAAAAAAAAAL!