This Dimension system is whisper quiet and a touch cheaper this week.
307-D08515 - £499 delivered
Intel® Pentium® D 805 Dual Core Processor (2.66GHz, 533MHz fsb, 2x1MB cache)
Genuine Windows® XP Home Edition (Does not include Operating System Re-installation CD)
1024MB Dual Channel DDR2 533MHz [2x512] Memory
160GB (7200rpm) Serial ATA Hard Drive with 8MB DataBurst cache
16x max. DVD+/-RW Drive
128MB ATI Radeon® X300 SE HyperMemory graphics card
Dell 19" Value Flat Panel (E196FP)
Integrated Audio with Dolby Digital 7.1 capability
Microsoft® Works 8.5 - English
McAfee® Security Centre 15-month subscription
90 days trial of Network Assistant included
Remember to reduce the warranty to minimum for this price and also dont forget to use Quidco for extra cashback.