Looking to get a laptop

Compaq Presario CQ56-111SA Laptop w/ Pentium T4500 2.3GHz 3GB RAM 15.6" LCD 320GB HDD
http://www.ebuyer.com/product/236680
Compaq Presario CQ56 review (not an identical match - 111SA has a more powerful Pentium dual core CPU)
http://www.notebookcheck.net/Review-HP-Compaq-Presario-...

Without already installed copy of Windows.
Pentium DC T4300 2.1GHz 2GB RAM 15.6" LCD 320GB HDD
http://www.ebuyer.com/product/240874

More in your price range:
http://www.ebuyer.com/search?page=1&store=5&cat=10&filt...[200+TO+499.99]&sort=pricelow&limit=10

Here is a Core i3 370 2.40GHz 3GB RAM 320GB HDD 15.6" LCD & Intel HD Graphics w/o OS in your price range.
http://www.novatech.co.uk/novatech/laptop/range/novatec...

The only recommendation I have is no matter what laptop you get, it will come with Windows. Don't forget to make the recovery discs. If you istall Linux the recovery partition might be erased. So if in case you need to go back to windows, you have the discs.