To be honest, I'd go with this rig.. (Dont know if you want a
decent G card or not?
Anyway;
AMD Athlon "Barton" XP2500+ 333FSB (Socket A) CPU - OEM (CP-039-AM) £61.69
Abit NF7 v2.0 nForce2 (Socket A) Motherboard (MB-035-AB) £49.94
Seagate Barracuda 7200.7 80GB 7200RPM ATA100 - OEM (HD-001-SE) £46.94
TwinMOS 512MB (2x256MB) DDR PC3200 Dual Channel Kit (MY-006-TM) £58.69
Coolermaster Aero 7 Lite (Socket A) (HS-007-CM) £15.86
That totals £233 inc VAT from
here
Doesnt include the case you picked.. as I dont know how it much it costs.. about £20-£30?
So thats about £260.. leaving you £90 or so for a G card. Depending what type of performance your after, You could go for a 9600XT (Which'l handle all current games) for just over £100.. or go for a low end 9600, about £80-90.. or maybe just a bog standard GF ti440 or something. Deffo stay away from PC chips.