Best Palm software?

I just got a Treo 650 and I'm looking for good software to put on it. So far I've downloaded Filez, a free open-source file browsing program, and MMPLayer, which allows me to play videos and music (although I haven't figured it out yet).

Any good games/apps/utilities that are must-haves for the Palm platform? I haven't owned one since I had a B&W m100 a few years back.