I think Rory and Spieth are popular picks, but Rory probably has a much better chance because he's playing well, and has been close before.
Personally, I'd like to see Phil win a fourth jacket, and then top it off with a US Open win.
Oosthuizen's albatross was on hole # 2 in 2012. I was in the bleachers at hole # 4 at the time. Phil was in contention and every one in the bleacher assumed Phil did something until they posted the score on the small leaderboard at 4. Phil's hopes of winning another Masters where dashed at #4. His tee shot into the par 3 went left and hit a 1/2 inch hand railing about 5 feet from where I was sitting. It bounced into the woods and Phil took a 6. It was pure bad luck and cost him the Masters. I'd say he has a good a chance as any to win this years event.