Nice upgrade. My problem with uprading my PIII is that I don't have a legal OS to put on it. That means I have to go Linux and I'm over my head.
In any case, if I do upgrade, the word on the street (Anandtech)is this is the best value for the buck/speed trade-off.
http://forums.anandtech.com/messageview.aspx?catid=40&threadid=1796551&enterthread=y
I use Linux. I prefer Slackware and Debian-testing for everyday use. I don't know much about the easy to use distros.
My only WinXP machine is the laptop.
Those three components(CPU, MB, RAM) only cost a total of about ~$300 at http://www.mwave.com/
I received it today.
It will be awhile before it posts a completed work unit though. It's first WU is a p2107, about 3 days. It is taking 16s per frame. My P3 500MHz also has a p2107 that it has been crunching forever.