I found that having the background data on, is what makes a lot of the apps auto-load. I kept closing them, and they would just come back.
Settings > Accounts & Sync > "uncheck" Background Data
After that you can close the apps you don't want on.
This made a HUGE difference in battery life. I can play games, and other stuff, all day long now. Before it just went like 2 hours max. You need to enable it for certain apps, and other stuff. But then just turn it off again. Also ... if you enable it (even briefly), check the apps that are running. A few have probably turned back on.
Mods ... Sorry if this has been mentioned too many times already