Hi,
Below's a copy 'n' paste from gedit, hows this for compatibility (not sure if I need to specify a distro for you to answer this, I'm running ubuntu 6.06)?
Also feel free to suggest better parts at lower prices (or lower prices!) thanks

:
Intel Pentium D 805 2.66 GHz (LGA775 Socket)
www.ebay.co.uk (Item no: 200005138943)
£79.99
ASUS P5GDC Deluxe Mainboard (PCI-E, SATA II, DDR2 etc)
www.epcbuyer.co.uk
£73.68
Western Digital Caviar SE16 320GB SATA II 16MB 7200RPM
www.microdirect.co.uk
£77.53 (-£2.31 Quidco Cashback) = £75.22
NEC ND-4570 Multiwriter Black 16x DVD±RW/RAM DL lead free (Drive only)
www.microdirect.co.uk
£23.39 (Combined postage costs with above item) (-£0.70 Quidco Cashback) = £22.69
Sapphire Radeon X1600 Pro 512MB GDDR2 / AGP / DVI / TV-OUT
www.pixmania.com
£95.06 (Combined postage with above 2 items) (-£2.85 Quidco Cashback) = £92.21
52 in 1 Black Flash Card Drive for 3.5" Drive Bays
www.pcnextday.co.uk
£9.99 - (Quidco Cashback -£0.29) = £9.70
1GB DDR2 NEW DESKTOP AENEON MEMORY 533mhz (2 x 512mb)
www.ebay.co.uk (item no: 230003057444)
£58.93
BenQ FP91G+ 19 inch SXGA TFT LCD 550:1 250cd/m2 1280 x 1024 8ms D-Sub/DVI
www.ebuyer.co.uk
£157.25
Aries Black PC Case with Silver/Black Fascia 300W PSU
www.savastore.com
£24.21
400W PSU for ATX PC Case
www.savastore.com
£11.73
TOTAL: £605.61
Thanks guys, the questions mainly about whether they'll be compatibility problems (with value for money as a side note!).