Thanks for everyones replies. With my budget I think I've settled on the Sigma f4.5-5.6. I've recently moved to Australia and found that camera stuff seems to be cheaper (everything else is more expensive than England). This site is very cheap, but worryingly so. It works out at about £280. Thoughts on whether its legit?
http://www.dwidigitalcameras.com.au/...?idProduct=720