Here's a list I'd suggest for you to have a look @ reviews and prices before you head to the shop and check which one feels the best in your hands.
Canon:
450D, 500D - second hand market might net you a cheaper price for 400/450D. (Not forgetting the 40D second hand)
Nikon:
D40, D5000 (or the D3000), maybe second hand D70 or D90.
Sony:
Any of the A2xx and A3xx seems to get suggested often. The A3xx series has in-body IS, so any lens you attach on the body will have IS, a bonus over both Canon and Nikon.
Olympus:
E420, E520 (loads in the second hand market as many have upgraded recently), you might even be able to get the E620 - which I highly recommend. Any Olympus E520 and above cameras have in body IS much like the Sony. Up side of the 4/3rd format is the smaller camera body and lenses - great for a camera you'd carry around anywhere and everywhere. Downside is, high ISO above 1600 will have fairly higher noise compared to the normal cropped sensor.
FYI, there's an Olympus E420 + 25mm pancake lens going for sale with a lot of basic kit e.g. CF cards and batteries + screen protector for £300 delivered.
Link Might perk your interest. The 14-42mm kit lens is also amazing which you can pick up for around £70 if you need a zoom lens.
Edit: OH YES! And I forgot, the Olympus E620 is still doing a promotion for the E620. It'll come with a grip and spare battery for free if you buy any E620. Ask the retailer for details (even if they 'sneakily' not shown on their site that it comes free.)
Good luck with your find

Also
www.cameralabs.co.uk is my usual place to look for reviews.