I suppose everyone else's mind is on the Desktop Summit in Berlin next week, but I'd like to take a moment to tout three conferences in the Netherlands later this year:
EuroBSDCon on .. well, everything BSD-ish, october 6th-9th 2011. There's a fantastic line-up of speakers, including PC-BSD's Kris Moore. That looks like the only desktop talk there, but the rest is equally nifty (not just because I like ZFS, SSH, SPARC and Dru).
NLUUG Fall Conference on IPv6 (and all the rest), october 20th 2011. The Call for Abstracts is open until August 1st, so not much time to drop a note (100 words is enough) to the programme committee. NetworkManager in transition would be a nifty topic, IMO.
PostgreSQL Conference Europe, october 18th-21st 2011. The Call for Papers is open until august 21st. All things Postgressy -- the last talk I saw about the 9.1 release was amazing in terms of features.