[INTEL]
Mobo: P5KPL-CM - INTEL G31 - 2500 /-
Procy: Core 2 Duo 2.80Ghz E7400 - 6050 /-
Ram: 2xOCZ 1GB DDR2 800MHZ - 1600 /-
GFX: Palit 9600GT 512MB DDR3- 5400/-
HDD: Seagate Sata II 160 GB -1900/-
Optical Drive: Samsung 22x - 1000/-
I assume you will reuse your cabinet and keyboard+mouse etc.
[AMD]
Mobo: Asus Nvidia M2n68-AM - 2250/-
Procy: Athlon 64 X2 7750+ 2.9GHz 3550/-
Ram: 2xOCZ 1GB DDR2 800MHZ - 1600 /-
GFX: Palit 9800GT 512MB DDR3 - 7075-
HDD: Seagate Sata II 320 GB 2375/-
Optical Drive: Samsung 22x - 1000/-
You will find that the AMD config is a tad more suited to gaming owing to the better GFX card.