Hehe I got a 180w hooked up to my 1700+ (secondary computer my main desktop is a 1700+ too...), but it's a special purpose PC that runs onboard everything a older HD a laptop dvd and that's it. (well exept for the pc card). It's also a microatx supply.
Power supplies are so dam cheap I'd get a 300 watt at least. It's cheap insurance, plus you can get nice ones with quiet fans. Many problems with stability that is blamed on motherboards or RAM (or the OS) is simply lack of power. Hell, get a 450 watt, even if you don't use it all, it will last forever and has plenty room for improvement for your next bunch of upgrades, or a hd raid setup or whatever you may want in the future.