Rishathra
Originally the subject of a controversy so ridiculous even Jack Thompson thought it was silly, Mass Effect included a scene where you got the nasty on with Calamari-Smurf ingenue Liara T'Soni. While Rishathra has been the topic of wishful (and extensive) thinking, singing, and recording by hopeful nerds all around the world. The options in ME2 are extensive and oddly detailed, probably in reaction to the controversy in the first one. That said, you still can't do anything with Wrex, poor fella needs a hug more than anyone else I can think of.