There's TONS of threads about battery life issues. The main issue that you'll see the most dramatic increase in life, is Google Talk, named "Talk" in the app list. Go into Talk and go to settings and disable "auto-sign-in". Then make sure you LOG OUT from those same settings. Now you're officially signed out of Talk, and it won't keep signing you in.
Basically, it searches for all your chat friends, and when they change they're status, it drains a little bit of battery each time. I saw a HUGE increase in battery after just doing this one, little, simple thing.