Want your battery to last all day and not drain even when in standby?

Just do the following:

1. Disable all the location services except the ones you really really really need. If you're not sure which ones you really really really need, then disable all of them and re-enable them one at a time as apps ask you to do so.
   
2. Disable Bluetooth. Seems like it's enabled by default on a fresh iOS 5 install.
   
3. Enable 3G or WiFi but don't leave both enabled.
   
4. Be sure to do a hard reboot of the device at least once after a fresh iOS 5 install. Or at the very least, reset your network settings.

(randomly I'm including a picture of a lady bug I took)