yeah Iphones offer shitty battery life. Some Android phones unfortunately too and Eris had very bad reviews if it comes to battery life. Only G1 had worse ones.
I do get a nice battery life as most other people with the same phone. To be fair though HTC usually offered below average battery life while some Motorola phones suck big time as far as battery goes. Also older phones offer shorter battery life because they use higher voltage cpus and LCD displays.
Actually I always read reviews on battery life before buying a new phone as I find that important.
New Samsungs offer very nice battery life though but they also use higher capacity batteries. Most new Samsungs have 1500mAh ones. Now if you think that Galaxy S offers a decent battery for a smartphone check out Samsung Wave
It handles almost 9 hours of HD video playback with 50% brightness.
A friend of mine has it and charges it every week. It's a pretty nice phone actually hardware-wise. Too bad Bada OS sucks balls. It doesn't even feel like a smartphone.