Single Core:
REFERENCE DESCRIPTION QUANTITY PRICE COST
CP-150-AM AMD Athlon 64 3700+ San Diego 90nm (Socket 939) - OEM (CP-150-AM) 1
£119.95 £119.95
FG-000-AR Arctic Cooling Freezer 64 Pro CPU Cooler (Socket 754/939/940) (FG-000-AR) 1
£12.95 £12.95
MB-046-MS MSI K8N Neo4 Platinum nForce4 Ultra (Socket 939) PCI-Express Motherboard (MB-046-MS) 1
£64.95 £64.95
MY-046-GL GeIL 2GB (2x1GB) PC3200 Value Dual Channel Kit CAS3 (GE2GB3200BDC) (MY-046-GL) 1
£89.95 £89.95
GX-048-PC PowerColor ATI Radeon X1800 XT 512MB GDDR3 AVIVO TV-Out/Dual DVI (PCI-Express) - Retail (GX-048-PC) 1
£199.95 £199.95
Subtotal £487.75
VAT £85.36
Total £573.11
The 3700+ SD is a good overclocking CPU, the MSI motherboard is a good overclocker but not to the extent of the DFI series. The Geil value RAM is better than the 'value' name suggests and can be mildly overclocked, and the X1800XT 512MB is a great 'bang-for-buck' card, I think it just edges out a 7800GTX/7900GT for the same price.
Dual Core:
REFERENCE DESCRIPTION QUANTITY PRICE COST
CP-152-AM AMD Athlon 64 X2 Dual Core 3800+ (Socket 939) - OEM (CP-152-AM) 1
£169.95 £169.95
FG-000-AR Arctic Cooling Freezer 64 Pro CPU Cooler (Socket 754/939/940) (FG-000-AR) 1
£12.95 £12.95
MB-046-MS MSI K8N Neo4 Platinum nForce4 Ultra (Socket 939) PCI-Express Motherboard (MB-046-MS) 1
£64.95 £64.95
MY-046-GL GeIL 2GB (2x1GB) PC3200 Value Dual Channel Kit CAS3 (GE2GB3200BDC) (MY-046-GL) 1
£89.95 £89.95
GX-048-PC PowerColor ATI Radeon X1800 XT 512MB GDDR3 AVIVO TV-Out/Dual DVI (PCI-Express) - Retail (GX-048-PC) 1
£199.95 £199.95
Subtotal £537.75
VAT £94.11
Total £631.86
Essentially the same as the single core spec but with an X2 3800+ dual core CPU. It has very good overclocking potential, though the 4400+ would be my choice as it is the equivilant of two 3700+ San Diego's, also has double the L2 cache over the 3800+.
*Edit* - You'll need an ATX2.0 PSU for a pci-e system.
