What new latest phone should i get with vodafone and why?

Ive been with vodaphone for nearly a year now and happy with the service etc and my contract is up soon for renewal.ive a sony ericsson k750i and i think its time for aa better updated phone but not sure what to get? any one know of any decent phones vodaphone compatible?
Answer
Sony ericsson w810i is hot but it has the same features as the k750i theres also the k800 cybershot which has a 3.2 megapixel camera and it looks quiet funky too or there is the n91 cool phone has 4gb internal memory, 2 mega pixal camera, mp3, bluetooth and it looks cool