Markov. Then when he retires, one of : pacioretty, galchenyuk, plekanec, tinordi, subban, gallagher.
Because Markov could still be playing for 3-4 more seasons in a smaller role.
I wouldn't give C to Markov at this point with what I've seen from him in the last 10-15 games. He obviously has slowed down significantly, and sure he can likely play for a bit in a smaller role. I wouldn't have much of a problem keeping him around as a PP specialist being our #4-6D on 5v5, I think he's still valuable this way.
But if he comes back as Captain, then there will be pressure to play him more, for him to produce, etc. that I don't think we should add to him or to the coach right now. Do you seriously think Gionta would be playing this much if he wasn't Captain? He's been as bad as Cole if not worse, yet he's been given every possible opportunity to shine, being sent in the SO twice, in 4v3 PP in a crucial situation (I still have a hard time with this one...), on most PPs, he's never been retrograded to the 3rd-4th line (although you could argue that he's on the 3rd line right now with Bourque out).
I think it's very hard to have your Captain being a fringe/role player (unless he was Captain of the team for a good 5+ years before in a dominant role), and I really think Markov is going there in the next years, his legs just can't hold.
I'd be fine with Gorges as C for the moment until a younger guy grows into the role in some years. For the moment he seems like the guy that should gets it, I don't see anyone else that would be a perfect fit, captaincy experience lacking aside.
But most of all, I REALLY want Gio gone this Summer. I can see how you wouldn't trade your C in the middle of the season, but I would definitely do it in the off-season, it's also easier for Bergevin/Therrien because he wasn't their guy. The team DOES need to get bigger, but the only sucky small player we have is Gionta, Desharnais and Gallagher are actually producing and still improving.