I recently changed my wi-fi settings to connect ONLY manually (no searching for signal) and it seems to have made a pretty significant improvement in my battery life.

I have a few widgets, including the Facebook one, but someone mentioned in another thread that if you are not on the homepage with the FB widget it will NOT drain your battery life by constantly updating. I think this is true b/c the widget only seems to start when I scroll to that page. I make sure that whenever I am in an idle mode I am not on the FB widget page and it seems to help.