This is the first place to look:
http://www.apple.com/macosx/applications/index.html
Aside from that these are my experiences:
OmniWeb browser is great.
http://www.omnigroup.com
IE is good. (comes with X)
Stone Design has some good (and temporarily free) image and html apps.
http://www.stone.com
Open-Up by
http://www.stepwise.com is good for uncompressing tar/gz files.
I'm already weary of the "Classic" interface and want to populate my computer with all Carbon and Cocoa applications so I'm hoping that other posters can add to my list.
I asked Lemke (GraphicConverter) if he was going to be doing an X version and he said he's looking at it. I'm really looking forward to a version of Eudora that is Carbon or Cocoa but I haven't heard if or when.
Downloadable demos/shareware/freeware:
TUCOWS says they're working on a separate MacOSX section.
Versiontracker already has one as does Softrak
http://greenapple.mac.tucows.com/mac.html
http://www.versiontracker.com/
http://softrak.stepwise.com
It may be worth getting AppleWorks. I think I will.
One thing I REALLY want, is some way to use the full range of resolutions of my G4's AGP graphic card and monitor. I can only get this thing up to 1280x The monitor and graphics card can do 1900x or better. Why is this limit here? Can anybody find me a utility or hack to correct this?