Only one?
Are you the only one disappointed by the battery life? Probably not.
But I'm not with you. Yes, wi-fi seems to suck the life out of the battery pretty quickly. But listening to music, it seems stellar. Better than my first gen nano, to be sure.
I'm guessing my time between charges will get better as time goes on. Not because of any change in the battery, but because I'll be able to walk past my iPod without picking it up to surf the net with it!