Well if you are Brand orientated then the 'better makes' will offer mere average performance for £500. I have recently seen Toshiba laptop for £479 with 160GB HDD, 3GB Ram yadda yadda yadda. Dells are dropping to around £400 for 250GB HDD 3 GB Ram etc...
Alternatively, I purchased an acer Aspire which has 1tb HDD, 4GB Ram, Blu-ray, DVD, CD-Rom Drive, HD Screen, HDMI Output and full multimedia settings for a bargain £499 from £579 in a sale (Equivalent top brands cost £750 upwards for these specs) and it runs fantastic just looks a little dated next to modern laptops even though internally it is modern!
I would nip into PC World, Comet and Curry's, ask the staff for there opinions then take a trip to your local Supermarket which offer laptops at a huge discount even though they are identical to the larger stores which specialize in them. (ie my wife's Laptop was £94 cheaper in ASDA than it was in Comet, came with free anti-virus for a year rather than 3 months trial, full Microsoft office package again instead of 3 month trial and she also got a carry bag for £10 instead of £30!) Shop Around!