Again, just for comparison, the HD2 is claimed to have 390 hours of standby battery time. Not sure if Android is more or less efficient..
HTC - Products - HTC HD2 - Specification
Nexus 1 is claimed to have 290 hours of standby time.
HTC - Products - Nexus One - Specification
The bigger screen will obviously use more power, but it appears the battery on the SS will have a greater initial capacity too.