For several months now I've set myself the rule that I only access FB from home; I've broken this rule only rarely and it's been remarkably successful at toning down the constant-checking behaviour---even when I'm at home. Because I've broken the "24-hour-IV-feed" nature of it, I've found that even when I have access to it I tend to spend a little while, check my updates, read a few things off the top of the feed, and then log out. And then I do other things.

Very helpful, and a nice compromise that stops short of "quitting facebook".