Chances are you'll want a new launcher. I have Launcher Pro and love it, there are some other good ones out there as well. If you install a new launcher, delete all the widgets on your default launcher first - otherwise they'll consume power running in the background.
Clockr Evolution is a good text clock if you like that.
Go to Amazon.com and download their appstore - they give one paid app away for free everyday, some suck, others are good.
Classic Tetris is one of the better original style tetris games
Driver Diary is a great app to log mileage / maintenance (since MPG hasn't been ported over from iOS yet)
Along that same line, GasBuddy will show cheapest prices around
Not sure if DroidLight works with that phone, but it's the best flashlight app I found for my DX
If you want to root and install different roms, start reading here:
http://www.droidforums.net/forum/droid-2-forum/ It's a great forum, and they have a dedicated app for viewing it as well.
- Justin