From what I've heard, Kim Yuna returned to competition recently and was in top form? At least, I know she won last year's Worlds with a massive lead over the rest of the competition. I think barring any injury issues, she's going to be incredibly hard to beat.

ETA: Though oh my gosh, I just saw an article that says this is going to be her last Olympics! Wow, I can't believe she plans on missing out on 2018 in South Korea…granted, by that point, she's likely to be past her prime...