I've actually been surprised, with the most recent Android xROM, I'm getting significantly better battery life than with WM, and of course far better than early Android. I keep GPS off and brightness at 60% almost always, but still, my battery seems to last around 20 hours with light use, and probably 12-14 with average use. I know the battery meter can't be off, since I've actually used the phone during those time ranges.
Edit: Oh, also taskiller (on the market and in a bunch of these builds) works great to kill apps you aren't using.
BRSEV | HTC Droid Incredible | VZW | Stock/unrooted...so far