BBC News - Matt Smith to leave Doctor Who at the end of year
Personally, as much as I like him as The Doctor, I think overall the writing hasn't been as good for the last year or so. I think they'll need more than a new doctor, but also a new writer, IMO.
That, and they just can't top Tennant. He's still the best, IMO.
Been seeing this all over. Will be interesting to see who the next Doctor will be.