Battery life is very much depend on individual usage. If your usage required constant data connect. Battery life will be very much shorten. IM, surf net, email and twitter will need constant data transfer.

Screen brightness also contribute to battery life. Some user crank up the brightness to maximum level.

Widgets that required interval update on Android also will shorten batt life. Adjust to longer update interval will improve it.

As a pure phone without any data. My Android phone can last more than 2 days. But when I start use data related Apps, my battery will be shorten to slight less than 1 day.