Tricky one, this. Ali deserves to go out because she's inconsistent and often dances like she's made of wood - wood with little natural rhythm at that.
Of the two remaining, much as I like Chris and his attitude to the judges' criticism over the weeks (all fair and he's certainly upped his game), I think Ricky is the better dancer. I would hope the final results reflect this. However, given Ricky's recent little bit of trouble (I've heard rumours that it was all a set up in any case), it will be interesting to see how the votes add up.