Batista's face turn was pretty fucking epic. I remember marking out like a little bitch. It made perfect sense, but I half-expected the WWE to fuck it up. The thumbs up with the fake smile, as Triple H and Ric Flair were applauding his decision to go to SmackDown!, followed by the pissed off look and the thumbs down was just awesome. And the Batista Bomb to Triple H through the table was just icing on the cake.
Batista was so cool then, probably because he was a smart heel that just happened to be on the opposite side to the bad guys. Kind of like an anti-hero of sorts. Of course, now he is good friends with little Rey, and is a defender of what is just and right.
It wasn't really a face turn, per se, although I guess it kind of was, but William Regal was fucking awesome during his shit with Eugene. When he came down and chewed up Triple H for being stupid enough for picking on the kid, because it's gone and turned Regal into his enemy, it gave me goosebumps. I know a lot of people like him as a heel around here, but as a babyface, Regal makes me mark.
Kurt Angle's initial face turn in 2001 was pretty cool to me, at the time. I was still fairly markish, but I loved it when Austin screwed over Kurt, or something, and then dorky Angle walked out, and Austin was like "hold on, Kurt," and Angle then stormed the ring all bad ass like.
But honestly, it was kind of rewarding to see the heel finally step up and believe his own hype a little bit, and kind of say "hey, I am good enough to kick anyone's ass instead of just saying I could, so I'm going to do it."
I'm sure there are more I am missing.