http://www.theinquirer.net/?article=31359 I find that to be pretty impressive. Granted it's Dell which I'm not overly fond of but just the fact they give you all that and still room for a new graphics card is pretty nice. So for between 300 and 400 pounds you're doing pretty well for yourself.
Well the site doesn't provide a link but it say's UK's cheapest dual-core PC as it's headline so I'm assuming it's around somewhere.