It certainly wouldn't be a shock to see any of these guys stay, but if I was a betting man, I'd bet that none of them will be taking finals next year (of course, that might be the case whether they're in school or not).
Here's how I would rank them as far as likeliest to come back:
1) Mike Conley
2) Kevin Durant
3) Greg Oden
4) Brandan Wright
What do you think these guys will do?