Ron, First of all, choose Universal Binary versions at all times if it's an option. Those are optimized to run on MacIntel hardware. Non-universal will run, but under the Rosetta emulator, leading to lower performance (but they run fine, just slower).
Handbrake. Freeware. And its sister Instant Handbrake. Converts DVD to video iPod format in one program. For iPod use only, use Instant.
MacMP3Gain, Freeware. *TRULY* normalizes audio files (MP3, AAC) by analyzing the entire song for average volume then setting them to the same average volume, not by the old (and highly inaccurate method) of setting peak levels the same. This has allowed me to have all 4000 songs on my iPod, all of which were mastered at very different audio levels on CD, to sound approximately the same volume, eliminating my need to change volume when louder/softer songs come on.
iLife - included with your system purchase. Check it out, buy a book if you have to. Garageband - great beginner music recording. iDVD. iPhoto. Photobooth. You get the point.
VLC Player - freeware, media player
Flip4Mac, freeware plugin, shareware option, plays WMV files on Mac.
How long until the new "Mac" subforum appears?
Let me know of your hobbies and I'll post some payware. Like:
Screewriting: Moviemagic Screenwriter or Final Draft.
Music Recording/Postproduction: Pro Tools LE/M-Powered or Apple's Logic Pro/Express
Video editing: Apple's Final Cut Pro
etc.