Surround Speaker Set

Hi,

 I'm just about to purchase a new AV system but dont know where to start with the speakers.  Here are the other components I am planning to purchase:

Sony KDL-40W2000
Sony STR-DA1200ES
Denon DVD1930

I have a budget of £2000 for the whole system which leaves me with about £500 for the speakers.  Some of the other components I will be connecting up - XBOX, XBOX 360, PS2, SKY HD, Wii and a PS3 further down the line.

Any recommendations would be greatly received.

Cheers,

Morg