There's one particular kiss that I rewatch a gazillion times, and that's due to the fact that it was one of the only real 'Holy Crap! They just smooched!' moments in the history of unexpected relationships that was...uh, totally, y'know, unexpected. That show Veronica Mars, which lasted three seasons, had, of course, it's title hero Veronica who investigated little mysteries here and there to make some bucks 'cuz she was good at it and pretty much a social outcast. Another character that started off as just a background dude with nothing to do but give off snide comments was Logan Echolls, a pretty rich boy who just didn't like Veronica at all.
Somehow, through the course of the first season, Veronica and Logan became united - sorta. They helped each other out of jams plenty of times, and I guess some sort of bond developed out of that. In "Weapons of Class Destruction", that messed up/mixed up relationship hits a giant crescendo as Veronica and Logan share a smooch at a hotel (after investigating a lead that ended up not really going anywhere). Something Happen's "Momentary Thing" blasts as the camera springs from one end of the hotel stairs to the other, Veronica and Logan totally going at the lip-locking like bunnies after the initial shock value wears off.
It's a great scene, awesome character progression, and one of the few instances where I was literally yelling at the screen and featured a giant grin on my face. Well done, Rob Thomas & Co. Oh, and yeah - go out and rent all three seasons of Veronica Mars, like, right now-ish.