At the moment Sony are dominating in the low/mid range market the a55 can be picked up for around £500 I believe. Your best bet is to head into to Jessops and try out the camera to see which you prefer, all photographers prefer different grips/weight balances. and you can get some professional advice at the same time
And when I got my Sony they randomly start chucking in free things to make you buy it I got my A330 which was worth £380, 3 years repairs cover (worth £70), SD card (Worth £15) and a case (Worth £25) for £400! so I'd head there and just try camera's out and see what deals you can get out of them