Offcourse do I use a PC. What a rediculous question. :-)
I have a Thunderbird at 1.4 GHz with 512 MB RAM, 80 GB HD and GeForce Ti 4200...........times 2. Yes, I have 2 iddentical machines.
Unfortunatly they have SD-RAM which gives about a 20 % performance penalty in games.
I still can play all new games so as long as I can do that, I won't be upgrading any of my machines. I probably won't sell them either because these are pretty fast machines to be given a new purpose.