I have a Probook 4330s which you can find for about £450 if you shop around (and even less if you have old hardware to trade in)
It's 13.3" and has a 2nd gen i5 processor, 4gb RAM, 1gb Radeon HD6490M, and a 640gb hard disk, or at least, the spec sheet says 640gb, mine actually came with a 750gb for some reason.