As an experiment I turned on my fully charged iPhone at 1000 AM today.
After three hours of very light use I am now at 65% of battery life left compared to 90% on my Droid which is seeing heavy use. By that I mean I have push turned off on the iPhone while the Droid is in full sync mode.
While I think today the Apple apps are better, my feeling is Android will catch up very quickly.
With data connectivity being so power intensive, the difference in battery life becomes a major differentiator when deciding which phone is best for you.