Jenna-Louise Coleman is going to be The Doctor's next companion, starting in the 2012 Christmas special.
News story: BBC News - Doctor Who's latest companion is unveiled
After seeing "The Snowmen", I think this is going to be a really interesting arc. I love impossible plots, so long as they actually explain them.
Clara Oswin Oswald has a great chemistry with the Doctor, and she's arguably as mad as he is.
On that thought, I believe her character would've been good as a female regeneration of the Doctor, if there ever were to be one.
One word. BADASS.
I love her. Though it's clear the Doctor is trying to find out who Clara is exactly.