I would say go for it! Max out the RAM for sure, install a decent 20GB or higher harddrive, and get a little USB WiFi and/or Bluetooth adapter. Don't go any higher than 10.3.9 for sure: you would have a heck of a time with Tiger, because I am assuming there isn't much L2 cache, and none of the bus speeds will be decent.

I've run 10.2.8 on a Bondi back in the day and thought it was an enjoyable experience, actually. 10.3.9 with upgraded specs plus a G4 = wonderful.