Maybe it's something else, then, but I don't know what it could be -- I don't have any background apps and I set it to ping for mail every 30 minutes. Maybe my LG does poorly when signal strength gets low? (AT&T coverage is spotty in Chicago, particularly near the lake)

But, I could use my old iPhone 3g for a couple of solid days, even listening to streaming music and doing stuff on it. With my LG Quantum, I'm almost afraid to turn the screen on to see if I have any text messages.