This is mine so far. I keep everything on, wifi, push email/contacts/calendar, 3G, notifications and location services on. I probably won't even have to charge it till well after 12AM and it's 7.32 pm now.
Terrible, IMO. My original on 3.0 easily had double the usage time. I restored the 3G S from a backup of my original so I know all the settings are exactly the same. When the screen is on I can practically watch the percentage tick down.
I've used maps (and thus the GPS) somewhat, but I can't keep it from locating me even if I don't press the button in the bottom left corner. Haven't even made any phone calls over 3G. Used safari only on WiFi (which is always on, as it is on my original).
For those of you with draining battery problems...Go to Safari and close all of your open web pages until you only have the White empty page left...then monitor your battery.