[gambatte]

I hate to predict battery life in hours 'cuz it is so subjective. If you read some of the posts, even some of the upgrade ROMs (e.g. WM6 and 6.1) are reported to impact battery life. The 1500mAh Seidio is your best bet in a "normal" size battery (most recommended) but I haven't tried it out 'cuz it is kind of pricey (2X price for 10-15% more power?).