My HTC Touch Pro2 goes 3-4 days between charges, using it as a phone, calendar/task/appointment manager, and some light 3G browsing (mainly Google maps when roaming unfamiliar territory in Shanghai or Xiamen).
What sucks batteries down is WIFI and GPS. Keep those turned off (or use them sparingly) and you’ll get multi-day battery life. But it kills all cell phones because of the way the wireless standards were set up. WIFI is a high power connection by design, and GPS requires high gain and power reception for location. You will not get low power versions of those features, by design.
My nephew has an Android and he told me I would never be happy with it because of the battery life. Sounds to me that Motorola didn’t figure it out after their RAZR battery disaster.