I have screen brightness very low (except when outside), have enabled no social network apps, no GPS and almost no activity besides mail checking (which doesn't do further automatic checks until you check it out). It handles about 1 day of usage.
Now, if you look at the battery specs for your
Galaxy Tab, jocampo, and my
Milestone 2, you see you clearly got the upper hand.
OTOH, mine is about the same as the
iPhone4...
I truly believe Android is more battery hungry.