1: DC10, no contest. Open air, daytime clubbing, music that you would never listen to at home but that gets right under your skin when you are in the place, mentalists from all over the world, super-friendly, (relatively) cheap, fantastic residents and not a big name in sight. Clubbing perfection.
2: Space. Apart from the daytime bit, it's the antithesis of DC10 - overpriced, overdependent on big names, far too cool for its own good but the music is great, atmosphere great and the Discoteca is the best club venue in the world.
3: Bora Bora, for many of the same reasons as DC10. Daytime clubbing is the best thing about Ibiza, you know it makes sense.
An honourable mention has to go to Amnesia, Cream this year was my first visit so I can't really comment but the ice cannon is great and the sound system is banging, it lets itself down a bit with the overcrowding though. I will investigate further on my future visits.