I prefer to rely upon the grapevine, the internet, and the personal communication more than on formal meetings but if you like socializing, by all means go. Just make sure that
1) You know which talks you want to attend and to which people you'd like to talk and are prepared to both sitting through the talks and the conversations. Nothing is as meaningless and time-wasting as sitting through a talk in which you understand only the speaker's name and affiliation, and nothing is as pathetic as a graduate student who tries to communicate with some expert and either has no idea of what he (student) is talking about or has nothing more interesting to say than "My name is ..., my adviser is ... , it was nice to meet you".
2) If you've made a poster already, take it with you anyway. Even if it is not displayed in the main hall, you may still have an opportunity to show it to some people (of course, it shouldn't be 8 by 10 feet in this case, so you may want to downsize it a bit).
3) In spite of what I said in 1) and 2), do not take the whole affair with beastly seriousness and have some ideas about what to do in the town or nearby for fun.
As to work, in most conference places you may find a quiet room or two (in the worst case scenario, just return to your hotel) where to spend some time alone between the events that really interest you. Unless you fly trans{atlantic/pacific}, you can reduce the wasted time to just a few hours, not days. As to the job market, if you are any good, the earlier you appear on the radar screens, the better. As to dollars, it should be your own decision: I suspect you'll not end up in the bankruptcy court or become a millionaire either way :).