These are some programs that I run on the Treo.
LJP is a program that emulates Nintendo Entertainment System, Sega Master System, Genesis, Super Nintendo, TurboGraifx 16 and more.
TCPMP is a free movie player that runs DivX movies, among other formats, at full framerate. It will playback 640x480 on the Treo's screen, automatically scaling to fit the native 320x320 resolution. This is very handy since you don't have to downsample or convert movies in your collection.
QuickNews is an RSS newsreader that I have configured to download podcasts. Several times a day, the Treo updates the RSS feeds. If it finds any new podcasts, it downloads them directly to the SD card. My Treo is always full of the most recent content.
Listening to Podcasts can be done with the included Pocket Tunes or TCPMP, for free. Shareware alternatives let you customize your music. The enhanced version of Pocket Tunes allows you to download skins for the player, and ties directly into Internet Radio streams. Listen to DI.fm or Soma anywhere you have data connection.
Mocean, a touchscreen-based player that uses a familiar wheel design, also plays audio and video. The interface makes it easy to transition away from other products.
Softick Audio Gateway allows you to wirelessly listen to your music through a pair of Bluetooth headphones, or anything else that receives Bluetooth A2DP signals.
Yes, it has Google Maps.