Personally, I like to have a clean dock, same as in my linux I have a clean launcher for xfce, and not very much on my desktop in windows or quick launch.

But, my dock contains these:

Firefox, VLC, iTunes, Terminal, Finder and Trash.

These are on the mac mini we have at my parents house though.

I will however probably have the same setup on the dock when I get leopard set up on my desktop system hopefully at the weekend.