My favorite festival, by far, has been Defqon.1
It's an entirely different atmosphere versus the States. I'm used some smaller events (Earthdance) and bigger ones (EDC, Ultra) but man was it mindblowing seeing how the Dutch do it.
They go all out with the theatrics, people are especially nice, there's no fear of narcs, if there were problems people resolved them quickly, and it was incredibly cheap.
Toss in some MDMA for the Saturday show and oh man... it gives me chills just thinking about it.
When you've got the right setting, music, and great friends and people around you -- you feel like you're part of a bigger thing. Hard to put my finger on it but all them troubles go away and you can be one with each other.