With enough RAM you should be able to run just about anything on it. The only catch is you won't be able to run the Tiger installer on it, since it doesn't have Firewire. It's possible to get it running on a machine that old, just a pain to get in installed on the Hard Disc. That's discussed at some length in this thread.

I currently run 10.3 on my iBook (a 366) and my iMac (a 400), and am pleased with how well they run.

I'd say max out the RAM (or put as much as you can afford it in), and go for a bigger hard disc. Then install whatever version of the OS you have, and prefer (I'd say go for 10.3, I like it LOADS more than older releases of OSX).

Good luck.