Titans vs. 49ers. I 100% believe that keeping Brady over Jimmy was the right move (two more Super Bowls makes it a no brainer), but I root for Jimmy to do well, and would be encouraged by the fact that Belichick was able to correctly identify the "next" guy, even if Brady's miraculous run made him redundant. It would give me a lot more hope for whoever we target after Brady.
I have no specific love for the Titans, but I despise the Chiefs and everything they stand for with a burning passion. So it's Titans by default. I also think that has the potential for the most physical Super Bowl, which I prefer.