I think that The Original Series is the most deserving of this magical one-extra year of televised episodes. I find the Man Trap even more lackluster as far as final episodes go. These Are the Voyages had a decent premise at heart and gave you closure...even if it is horrible, horrible closure on Trip's part. But the Man Trap doesn't really have much to brag about and now that we're in the late 2000's it's views on women are kind of back wards by now. Especially after we've had a series helmed by a female captain.
But personally, I'd give it to Enterprise. Enterprise was the first Star Trek series I watched start to finish in conjunction with their air dates so it holds a special place in my heart even if season two strained my patience a bit. Coto supposedly had the idea that Shran would have become a crew member on the Enterprise if season 5 would have come along. Oh man, that would have been cool. And a visit to Denobula, a visit to the Cloud planet, another Mirror Universe episode centering around Empress Hoshi; yeah, I could easily dig all of that.
So I voted for Ent. Sorry, TOSsers.