In no particular order:
Lois and Clark - Ours, of course. Some of the best on-screen chemistry ever. There are many other couples I love, but few have chemistry this good. I'm not talking about heat here, but that connection between them seeming present and real and you just want to see them on-screen together.
Simon and River Tam - Siblings from the show Firefly. They have great, great on-screen chemistry, IMO. I feel that relationship. From the first time they're on the screen together, it's just so powerful. It is one of my favorite relationships (of any sort) that I've ever seen in any fandom.
Paul and Victoria - From the movie A Walk in the Clouds. Not the best movie ever. Heck, I had to look up his character's name. But the chemistry there was just fantastic to me. Rarely does sexual tension actually rate with me. Very rarely. With them it did. I could just feel how much they wanted to touch each other and be together. And their love scene (or would-be love scene, if you prefer) is perhaps one of two love scenes ever where I have actually seen heat and emotion in a love scene. Or either individually, actually.
Kyle Reese and Sarah Connor - From the Terminator movies. It sort of develops along the way. Their love scene is the other one of the two ever. And the cut scene from T2 - makes me mushy inside and I want to cry and it just works so well and wonderfully. I absolutely love them. Hope she doesn't have love interests in the show, because I just couldn't see her wanting anyone else. Recovering and moving on with life is great for some characters (Zoe, from Firefly), but not for her.
That's it for now, but I might think of some others that need to be on my list and come back and add them.
