I attended and organized conference, I believe it's a good way to learn and meet interesting peoples, I don't like mainstream conference to be honest (like the ones organized by vendor or the techno centric ones, I don't like tutorial like talks ;o) ), but more conference which will give you new insights and to think out of the box. In general what I like the more in conference is the discussions with people between talks and the workshops (if there is workshops options before or after conference take'm and pick some hands-on sessions in conf).
The conference I initiated with a friend is NCrafts (in Paris, France go for it if you can ^^) Other conference that I love : Buildstuff (EU), Codemesh (EU), Lambda days (EU) and StrangeLoop (US)
Notice that all this conferences publish the videos in their website, so the point for attending in person is to take proper times to do it (because you will never take the time to watch all the videos you want lol) and to share with others, the discussions are the most valuable think in conferences.
My 2 cents