I'm not a Mac user (yet) but I found a software for image editing. From what I've heard it's similar to the GIMP so you might want to add this to the list.

Seashore

Also, here's a Mac version of Soulseek (P2P programs)

soulseeX

This post has been edited by Sheonix: Oct 20 2005, 04:14 PM

Transmission

A simple and clean BitTorrent client that gets the job done.

Handbrake

DVD ripper/converter. Made by the same team who brought Transmission.

OnyX

Great and free maintenance and personalization tool to keep a healthy OS X system.