X Freeware

GIMPshop

http://plasticbugs.com/?page_id=294

Almost all of the features of Photoshop at an infinitely smaller price. Based on the GIMP base, but with a more Photoshop-like interface. Requires X11 but you can find that on your OS X install disc. And they just released a Universal Binary too.

Google Earth

http://earth.google.com/

If you don't know what this is yet, you've been under a rock in the middle of Australia. Check out your house with this.

iPhoto Buddy

http://nofences.net/iphotoBuddy/

If you have a LOT of photos, this will let you manage multiple photo libraries.