I've only had mine for about a week now, and usually get about 12hrs +, with auto screen brightness on using around 4 hrs of on screen time, 1 hrs GPS usage, streaming Pandora for about 1 1/2 hrs. and checking emails, facebook and reading. I've only seen the temp go up to 102F. What I have noticed though, is even with 2GB of RAM, I have been down to about 300 MB of RAM. So I use the stock app manager and close apps, I know I won't be using in awhile. I have also disabled apps I won't be using too. Also, I clear the running apps list. This seems to help with battery drain and temp. I have a lot of games on my phone, but I'm not a heavy 3D gamer.
Edited: Forgot to mention I'm on wifi 90% of the time and use bluetooth for about an 1 hrs.