I'm pretty sure the first time I romance him it will be with a Qunari mage, but I just gotta try a Dwarf eventually... think of the awkward cuteness potential. 
I will do romance just because I think its funny. I've done it with Male Shepard and Garrus (used save game editor) just for that reason alone. Most of the time, it usually has do with what my character is getting out of the romance since in real life I don't care about that. I have to find that character very interesting. I always like to see dynamics between characters, interactions, character development, etc. Even more so since I want to do some writing myself on the side.