Unabashedly Marcurio. He's hilarious, snarky and has such a cute voice. And the funny thing is, if I run into any other NPCs with the same voice, I instantly and automatically latch onto them as well no matter the situation.
However, Farkas was the only man I ever married, back in my very first game. We cut through the Silver Hand as one, mourned the loss of our leaders, cured our lycanthropy together, settled down in Riften and after a long time wondering if it was safe for the Dragonborn to take her husband on dangerous adventures, I made him a suit of Daedric armor, uber-enchanted it and we spent the rest of our days happily adventuring in the wide world together.
And this may be the oddest opinion in here, but I honestly kind of like Farengar. He puts up a snobby front, despises most people who cross his doorstep and elevates his research above all else, but I can't help but think that he's lonely, alone in his office all day.