There's a space for both. Sometimes, the only course of action is to sit and learn. That's what I did the first few times - I knew very little and very few people, so that was my preferred option. Others are targeted at corporate types who just want data dumps - these are usually the expensive ones. There's no one right way and you have to choose the best mix.
This year I will go to *camps (bar/pod or whatever), conferences such as Gnomedex and SXSW where there is a lot of stuff happening in and out of the rooms; I'll virtually attend (Web2.0 over the last few days) and I'll go and sit and listen only in industry sessions. All of them give me something, and I balance that against my needs (for work or just pure knowledge), the costs (and who's paying) and the effort involved in getting there! I do my best to take something out of it regardless of the format.