iTerm is a wonderful thing; I missed aterm and Eterm from X11, and this brought back all the stuff I missed.
If you're using vi thru SSH (ie. on another machine), I suspect it's just an environment variable that needs setting, or the shell used doesn't have color enabled — some of the older shells don't.
If not… For some reason, the version of bash installed under Panther has no color to it. I can neither get color 'ls' listings, nor do I see color in vi / vim. For that, I have no answer yet. v2.05b0 should have color…
I believe this is an appropriate time to simply say WTF. :-)