GUADEC last year in Birmingham was terrific. The technical tracks were terrific, with content on a level that makes events like Apple's WWDC look like mere marketing vehicles. Oh, wait... um...
Anyway, if your idea of a technical conference is discussion of topics ranging from basic to esoteric, groups of people huddled around with their laptops banging out code, and a few folks sound asleep in the middle of the venue floor after all-night hacking sessions, GUADEC is for you. Oh, and the attendees are fun and the parties are great.
I expect this year in Istanbul to be at least as good, and hopefully better.
There's also a GNOME summit in Boston over Columbus Day weekend in October, kind of a micro-GUADEC on this side of the pond.
