Anybody got any suggestions on the best combination to get the longest life out of battery.
Sure.
Leave GPS and Bluetooth off except when you have an app that is specifically using one of them.
Set WiFi to turn on when the tablet wakes and off when it sleeps.
Only set programs to sync if you need them to sync, and then at the longest intervals possible. Mail programs can be real offenders here.
Instead of using auto-brightness for the screen, fix the setting as low as will work for you.
Don't use task killers. If you need to force close a misbehaving app, use
Settings>Applications>My Applications>That App>Force Close
Check what's using your battery and turn off any offenders:
Settings>About Tablet>Battery Use
You've now done everything programs like Juice Defender can do for you.
Your Thrive should use only about 1/2% of its battery life per hour when it's sleeping. If it's much worse than that, go back through the troubleshooting steps.