Acer Desktop computer (£399.99):
http://www.comet.co.uk/shopcomet/product/440019/ACER-ASM3600-3630

HP (339) no monitor so add (150) for monitor best choice
http://www.staples.co.uk/ENG/Catalog/cat_sku.asp?Description=UK_CL_Desktop+PCs&CatIds=21797,35750,21827&webid=393663&affixedcode=WW

Acer 2 Ebuyer (399)
http://www.ebuyer.com/product/138615

Mesh PC(499) (fastest spec seen)
http://www.meshcomputers.com/Default.aspx?PAGE=PRODUCTVIEWPAGE&USG=PRODUCT&ENT=PRODUCT&KEY=326919

Teaser (over budget) (599)
http://www.aria.co.uk/Products/Systems/Gladiator+Atlas/Gladiator+Atlas+Pro+PC+System+?productId=29799
http://www.aria.co.uk/Products/Systems/Gladiator+Proteus/Gladiator+Proteus+Vista+Z100+PC+System+?productId=29430#rqc
http://www.saverstore.com/productinfo/Product.aspx?product_id=20018185&rstrat=13636

Ignore below
Toshiba Satellite Pro A200GE-1F9 (This I think is better than the acer, but more expensive..)

  • From laptops Direct £849

    From CCL £875
    from technoworld (£50 cashback from toshiba) £872

  • * Processor: Intel Centrino Core 2 Duo Processor T7300
    * RAM: 2048MB DDR2 667MHz Maximum expandability: 4096MB
    * Hard Drive: 250GB Certification S.M.A.R.T
    * Display: 15.4" Toshiba TruBrite WXGA TFT (1280x800)
    * Optical Drive: DVD-RW Super Multi Double Layer
    * Wireless LAN: 802.11a/b/g integrated
    * Warranty: 1-year international warranty. (Upgrade your standard warranty with Toshiba warranty extension, uplift and all-risks insurance packs.)
    * Battery life: Currently no official Vista battery benchmark result available
    * Dimensions: (W x D x H) 362 x 267.8 x 33.5 (front)/39.3 (rear)mm
    * Weight: Starting at 2.72kg
    * Expansion slots: 2 x memory slots (1 to configure), 1 x ExpressCard slot
    * Interfaces: 1 x DC-in, 1 x external monitor,1 x RJ-11, 1 x RJ-45, 1 x TV-out (s-video), 1 x i.LINK�(IEEE1394), 1 x external microphone, 1 x headphone (stereo), 1 x 6-in-1 Bridge Media slot (supports SD Card, Memory Stick, Memory Stick Pro, Multimedia Card, xD-Picture Card, SDIO), 4 (Left 2, Right 2) x USB 2.0, 1 x integrated 1.3 Megapixel Video Camera
    * Security: main battery pack (by sliding latch), system password security, wireless LAN switch, user password, main hard disk (by screw), supervisor password, slot for Kensington Cable Lock, main memory (by screw), BIOS password.
    * Operating System: Genuine Windows Vista Business Edition

http://wiki.opensource.nokia.com/projects/Internet_Radio_User_Guide