Let's assume we've another two years of Ferguson...
Mourinho, if he goes to Chelsea in the summer there's no chance. If not, then I'd suspect he's lined himself up for the United job.
Guardiola, I'd expect him to do at least three years at Bayern, and after that he may take another break from football. So probably not him.
Klopp, he will more than likely move on from Dortmund in the next few years, and he has expressed an interest in managing in England. Currently likely.
Solskjær, still a massive ask to jump from Norwegian football to Manchester United. I still think United will not move for him directly from Norway, but rather wait to see how he does in his next job, wherever that may be. Definitely could be one for the future, but it may be too early for him to succeed Ferguson.
Giggs, think he's an interesting proposition. But the lack of experience is worrying there too. So, like Solskjær, I'd expect him to have to gain experience elsewhere before getting the chance at United. Then again, he could be another Guardiola, we just don't know.
Villas-Boas, if Tottenham progress and cement a place in the top four, then he's an outside possibility.
