Harbaugh's a tough one - I'd rather him go to the NFL soon, because if not he would end up a Wolverine, and that would suck. Gruden has said that he's enjoying his cushy gig right now and doesn't want to leave Florida. Same with Cowher and Carolina (which might make sense if Fox is out.)
I feel like an offensive minded coach would be the direction that this team needs - someone that can develop consistency within the team. Pair him with a solid D Coordinator, and you're set. Jason Garrett might do a nice job. The Dallas offense was always pretty solid when healthy.
I would love for the Titans and Fisher to cut ties - he does well with what he's given. I think a lot of people underrate what he's done in Nashville. Coughlin is pretty tough and demanding, which seemed to work to a point in NYC. Not sure what went wrong there, or if it would work here.
Gruden would be my first choice, though. Then Fisher, then Billick, for some strange reason, and then Garrett.