my wife has the HTC Desire, sed it heavily in phils last 2 weeks and no problems with battery even though she was in facebook a lot of the time.
I've turned off bluetooth and active wallpapers so i think that's made a lot of difference
Maccaman and Madmarky have theis phone too, try PMing them for input.
as for the iPhone, it's from apple (can we have a "Burn it with Fire" emoticon?)