I looked through all the desktop deals for the cheapest system with a 19" TFT and this is the result.
Remember to reduce the warranty to minimum and buy via Quidco for further cashback savings.
Recommended upgrades: AMD® Athlon 64 Processor 3800+ add £18
305-D11C16 - £379 or less delivered
AMD® Athlon 64 Processor 3200+
Genuine Windows® XP Media Center Edition 2005 (Incl Operating System Re-installation CD)
Dell 19" Value Flat Panel (E197FP)
512MB Dual Channel DDR2 533MHz [2x256] Memory
160GB (7200rpm) Serial ATA Hard Drive with 8MB DataBurst cache
16x DVD +/- RW Drive
Integrated nVidia® GeForce® 6150 LE graphics
Imaging Promotion - FREE Dell Colour Printer 725
Dell 2 Button USB Wheel Mouse - Black
Integrated 7.1 Channel High Definition Audio
Microsoft® Works 8 - English