[MichaelJPR]

I've got a couple of hundred bucks burning a hole in my pocket. If you were me, what little gadget for your Mac would you buy? I'm thinking of either a 16x DVD burner or an external drive. I have an 800 iMac G4 with a 1x burner and the hard drive has like, 7 gigs left available.

[Cadaver]

Dual layer DVD drives are nice (and spacious), but if you don't frequently use your burner for this, than it wouldn't be worth it. Plus, dual layer media is still expensive, floating near $5 per disc. Depends on how much you use your DVD burner....
A fast hard drive can make the computer seem like new. You can get a nice performance boost from a good, fast hard drive. Apps will open faster, searches finish in less time, file saves will complete faster, etc.
More RAM is always a good thing to get. You don't say how much you have now, but with OS X, you can almost never have too much.
Don't forget to budget $129 for MacOS X 10.4...! That should provide a very nice upgrade.