Aside from Lee and Kara, the other couple on BSG with compelling chemistry IMO is Laura Roslin and Bill Adama.
I love this photo of them (despite the pornstache) because they look so contented and peaceful for once! And later in the episode when they get high...it was getting too close to comfort there! While I think it would be great for them to be together - I mean, really together - I understand too why this just cannot be. The president of the colonies - such as they are - and the head of the Colonial Fleet - such as it is - romantically linked would be too much pressure for them to bear not to mention awkward. It's an interesting contrast to Kara and Lee's relationship - with K/L, they each choose their misery in their own ways. With Laura/Bill, the misery chooses them...that is, they are in an impossible situation as the fate of the human race is in their hands. No comparison really!
The beauty of their scenes in "Unfinished Business" is that it gives the audience a glimpse not only of what New Caprica was like in its early days but also of what life could be like without the constant threat of Cylon attacks. We get to imagine the possibilities of an existence where a teacher and a soldier could be happy together in a cabin alone near a stream of clear water in the woods...