I definitely have to say the C's. They faced the Lakers, their #1 rival, and beat our nemesis Kobe. And this was in the finals. Sure Tampa Bay is a talented team, but it would have felt like a bigger comeback if the Sox had been playing against the Yankees. I almost expect crazy stuff like blowing 7 run leads from Tampa anyway.
And I think the comebacks in 04 against the Yankees were greater than last night. Just remember game 4, most had given up on the Sox ever getting past the Yankees in our lifetimes to get to the WS. And then they somehow did it with heroics from several players. Games 4 and 5 were better comebacks in my mind, and I'd probably rank them above the C's beating the Lakers in game 4.