TTL - Nissin Di622, YongNuo YN465/467/468 or the Jessops 360AFD
Manual YongNuo YN460-II/560
All are well within budget, the Jessops flash is probably the "safest" buy as you'd get a warranty with a high street retailer, followed by the Nissin (7dayshop etc). The YongNuos would have to be bought from the likes of Ebay, so you have to decide if that's worth the risk or not....