So my ritual goes like this. Has for every phone I've owned, though the Thunderbolt seems to be worst impacted.
1: Use phone all day. I don't do phone calls. Occasional web browsing, infrequent GPS/maps/traffic, lots of email and calendar.
2: When I'm ready to go to bed I plug the phone in. It then serves as my alarm clock. Does this reasonably well - though pale in comparison to the Fascinate with the dock, but that's another issue.
3: Wake up in the morning, the phone is fully charged according to all indicators. Unplug it, the screen goes off. It's 6:20AM or thereabouts. Do my usual morning prep.
4: 7:45AM, I'm in my car, check my calendar. I notice the battery has dropped from what I thought was fully charged to 75%.
Haven't touched it for that hour. Screen is off so I know it's not that. Full wireless but no data. Sync is set not to automatically do anything until 8AM. No streaming anything, no Bluetooth, no GPS, nothing.
For the life of me I have no idea what could possibly be eating the battery that much.