This one looks like top value with fast ram, big hard drive and 15 months McAfee thrown in.
307-N08945 - £749 delivered
Intel Core Duo Processor T2300E (1.66 GHz, 2 MB L2 cache, 667 MHz FSB)
Genuine Windows® XP Home Edition, SP2 (incl Symantec PC Restore Recovery)
1024MB 667MHz Dual Channel DDR2 SDRAM (2x512)
120GB (5,400rpm) Hard Drive
Fixed Internal 8x DVD/24x CDRW Combo Drive With Software
Intel® Media Accelerator 950 Graphics Up to 128MB shared graphics memory
Integrated Sound Blaster® Audigy® ADVANCED HD Audio- Trial Version
Intel® Pro Wireless 3945 802.11a/b/g Mini PCI Wireless LAN Card for Duo Processors
6 Cell, 56Whr Lithium Ion Primary Battery
Network Assist - 90 Day Trial
Microsoft® Works 8.5 - English
McAfee® Security Centre 15-month subscription
Dell Media Experience 3.0 Basic
Reduce the warranty to minimum and buy via Quidco for further cashback savings.