I purchased a 3600mAH battery off ebay after reading this thread. I was astounded at how thick it made the phone. But where the looks of it lack, performance more than makes up for. I pulled this battery off the charger (its first full charge) 26 hours 32 min ago from right now. Yesterday I abused it pretty bad. Also was at work where I constantly go in and out of service all day. Last night I had it plugged into my speakers and played mp3s off of it for roughly 5 hours straight. Right now my battery is at 37 %. I was pretty excited about conditioning it (fully discharge/recharge 5 times) and starting normal use with it but it looks like that might be next month some time at the rate this things going. Must have in my book.
For the rooted guys: I run this thing at 1.5 GHz with a performance governor. When I started running this setting a while back it very much degraded my battery life. I did some digging and found a few system apps the eat away at the battery that you don't really need. After freezing these apps I got a lot my battery life back. Apps: Bluetooth Test, BrcmBluetoothServices, com.sec.android.app.lcdtest, Factory Test, Shutdown App, VPN Services, Wifi Sharing, Wifi Sharing Services, and Wlan Test.