I'm pretty torn between three choices.
When it comes to a promo that took you by surprise as to how entertaining it was, then Bryan & Kane at anger management is the clear winner. The overall angle of Team Hell No could've been a complete disaster and quite possibly would have been had it been anybody else but Bryan & Kane. They surprised a lot of people with their unique chemistry and made what seemed like a comedy tag team, at least on the surface, into probably the most interesting tag team in wrestling this year.
If you're more into something with a lot of old school passion, then Foley's exchanges with Punk is the way to go. Punk & Foley's promo segments with each other were nothing short of outstanding and they played perfectly off of each other. Foley's passion really shined through and his unmistakable passion is a big reason why he became such a big star.
If you want a promo that generated tons of buzz, then Punk & Heyman mocking Jerry Lawler is it. In my opinion, I think this shows that most people really don't want the Attitude Era back. This promo is exactly the type of stuff that was fairly common back in the late 90s. I personally enjoyed it because it's the only thing we've seen in all of pro wrestling in quite some time that was genuinely controversial. Real controversy, and not the tired cliches that Attitude Era marks spray their shorts over, is supposed to get people a little upset and make you uncomfortable. This segment did that while still featuring great mic work from Punk & Heyman. It made Punk & Heyman look despicable and, surprise surprise, that's what most heels are supposed to be.
I'm going with Punk & Heyman because of the buzz and controversy it generated. I know it won't win, as so many people were offended by it and/or took the mocking to heart for some reason, but I enjoyed it a lot. If Lawler hadn't agreed to it and been in on it, I doubt I would have. If the man that had the heart attack had no issues and even encouraged the angle, then I I've got no problem with it. My grandmother died of a heart attack back in 1990, yet I know WWE wasn't casting a broad net to poke fun at heart attack victims in general.