With a battery saving app like Juice Defender (I paid for the pro version. Well worth it.) I can go all day and only use 30% battery. (Assuming I don't use it at all.)
If I use the phone lightly, by the time I get home (average a 9 hour work day) the battery is usually around 30% left. (Lightly=10 5 minute phone calls, a couple texts, maybe a Google search or two.)
Use the phone for an hour heavily (use the external speaker to stream Tune-In radio) and the phone dies within that hour.
You can get (I plan on it soon.) an extended battery that should extend life by a bit. I want the one that also lets me charge it wirelessly.