I used to use outlook years ago.  I switched to thunderbird and now use Gmail as my email client for everything.  However I recently became aware of something that might convince me to move back if I didn’t need my email at multiple sites. Read More Below...

The program is called Xobni (inbox backwards) and while I could write about it their intro video says it best.

It’s currently in public beta and is free but WOW. I could use this now! Check out Xobni.