I'm about to set off in the direction of the leading European educational research conference EARLI, which is about to start in Exeter. I say "set off", but it's not too many paces away... Exeter is a wonderful city, by the way!
I've not come across too many conferences to which I want to return, but the biennial EARLI conference is an exception. It's too large, really, (5 days of 23 parallel sessions?! 4 parallel keynotes at a time?! A 2000 page book of abstracts?!); its submission deadlines are ridiculously long (10 months in advance, this year); and technology is not as strong a focus for EARLI as it is for several other European conferences. But in my experience the papers at EARLI tend to be of a higher quality and the discussions more thoughtful than elsewhere.
It may be a bit late now for you to get to the 2011 conference, but luckily this year the keynotes are being webcast, and anyone can join in the discussions. Here is the link to the EARLI Virtual Conference.
You might also be interested in its sister conference EAPRIL, which is the "European Association for Practitioner Research on Improving Learning". I've not attended EAPRIL, so I can't vouch for it, but it looks very relevant to those who are interested in practice-based research.
The 2011 EAPRIL conference is in Nijmegen, in the Netherlands, 23-25 November. There's still time to submit a paper: the deadline is 14 September. Details at http://www.eapril.org/EAPRIL2011