Alesha, by miles. She's got so much charisma and natural dance talent, I can't take my eyes off her. She was at least as good as Penny and Kelly on Saturday, IMO. (And Gabby was also undermarked, but that's another story for another day....)
p.s. of the boys, John's the best dancer. Dom's got the watchability factor. Gethin won't get anywhere, because he spends half the week chained to my bed. RAAAAAAAAAAAARGH