Yeah just one more heads up - signal strength will indeed make a big difference in your battery life. If your phone loses signal and starts searching for a tower, it's burning mA like a stock broker looking at a 700 billion dollar bailout
So if you're noticing you flip in and out of roam often, or you know you're in a marginal signal area, your battery life will be far lower then someone else with an identically configured device but in a very good EVDO signal area. I mention EVDO because that too is far more battery friendly then 1X data. If for no other reason that to send/receive the same number of bytes the radio has to be ON vs Dormant a lot longer in 1X mode....