The budget is pretty tight but this ought to be suitable, I think I've included everything. However if it must be £600 on the nose you could change the case for the Antec NSK4400 with a 380w PSU, this may limit potential overclocks though.
Hitachi Deskstar 7K160 NCQ 160GB SATA-II 8MB Cache - OEM £29.99
(£35.24) £29.99
(£35.24)
LiteON DH-20A1P-45C 20x DVD±RW x12 Ram Dual Layer DVD-Writer (Black) - OEM £14.99
(£17.61) £14.99
(£17.61)
Antec NSK6500 Super Midi Tower Case - 430W PSU £58.99
(£69.31) £58.99
(£69.31)
Logitech S96 PS/2 Optical Wheel Mouse Black - OEM £4.49
(£5.28) £4.49
(£5.28)
Logitech Deluxe Keyboard (Black) - OEM £5.49
(£6.45) £5.49
(£6.45)
Microsoft Windows Vista Home Premium 64-Bit Edition DVD - OEM - 1Pk (66I-00788) £63.99
(£75.19) £63.99
(£75.19)
OcUK Value Hanns-G HW173D 17" Widescreen LCD Monitor - Silver/Black £74.99
(£88.11) £74.99
(£88.11)
Gigabyte GA_965P_S3 (Socket 775) PCI-Express DDR2 Motherboard £59.99
(£70.49) £59.99
(£70.49)
Asus ATI Radeon X1950 Pro HTDP 256MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail £89.99
(£105.74) £89.99
(£105.74)
Intel Core 2 Duo E4300 "LGA775 Allendale" 1.80GHz (800FSB) - Retail £65.99
(£77.54) £65.99
(£77.54)
GeIL 2GB (2x1GB) PC5300C4 667MHz Value DDR2 Dual Channel Kit (GX22GB5300DC) £44.99
(£52.86) £44.99
(£52.86)
Sub Total : £513.89
Shipping cost assumes delivery to UK Mainland with:
City Link Parcel Next Day (Delivered Mon-Fri)
(This can be changed during checkout) Shipping : £12.95
Vat : £92.20
Total : £619.04