Just check out the website to see some of the incredible art created with this painting program. If you're artistically inclined, you'll want to take this one for a spin.
It's a full-featured vector graphics program along the lines of Illustrator or Freehand. It was recently acquired by Microsoft and, for reasons unknown, is available for free. Get it while you can from MacUpdate.
Use a whole bunch of little pictures to make a big picture -- and maybe make a statement while you're at it. The examples shown at the website tell the story. An alternative is called MozoDojo
PhotoRetouch DigiCam does indeed touch up your photos. Improve them or warp them for fun. This free version has a lot more features than you might expect.
PixelNhance is the best of the bunch, but unfortunately it's hard to find since the developer has discontinued it. Caffeine Software has a download link that works as of this writing, but unfortunately it hasn't been reliable in past.
RagTime Solo is a free — and virtually identical — version of the RagTime desktop publishing program. If you can't afford Quark or InDesign, and want something more flexible than the DTP abilities of a word processor, this might be the program for you.
It's full of cocoa and open source goodness, so it's worth keeping an eye on this program as it develops to its potential -- a free version of Photoshop?
Toy Viewer has the kind of name that makes it hard to take seriously, but Charles W. Moore at Applelinks highly recommends it, and I find his views to be credible for the most part.