Don't buy an AMD processor for as much as the 3200 costs - buy the highest intel for the same price.
Do you really need that much? It all dependsonwhat kind of games you'll be playingand how often. If you're a casual gamer something like a Radeon 9200 would do fine for a video card, and they're cheap! if really heavy then go for that high of a video card.
You don't need 2 gigs of ram - I've got more than I need at 512 on my big machine - and will be buying a new computer with 512 megs soon - just upgrade when you need more :/
As far as cooling goes- if you do get the athlon - get a volcano fan - it sound like a freight train in your bed room but it cools very well, and just a few generic case fans, usually gaming PCs necessitate atleast 2 case fans.
As far as power supply goes - more than 350 watt - I have a 500 in mine.
New PC (Finished May 4, 2004)
Athlon XP 2800+
Soyo Dragon ultra Platinum KT600
1024 MB Kingston Hyper-X
120GB 7200 RPM 8MB
160GB 7200 RPM 2MB
GeForce FX5500 256MB
16x52x32x52 DVD/CDRW Combo