Kaidan, Carth or Alistair?
Kaidan without a doubt. Why? Because he's a man, I don't have to handwalk him through stuff. He knows his job, he respects you, he watches your back both in the field as in private, he can listen as well as voice his opinion and unlike a lot believe, he DOES NOT whine.
Carth, yeah he whines but I still love the guy. He's tough and has a great sense of humor though his suspicions can get tiresome. Still he's just a little behind Alistair for me, maybe even on the same level.
Alistair, good looking, lovely voice, but ....too much handwalking. In Dragon Age, my Cousland warden needs someone to hold her hand on occassion you know. To tell her it will all be alright, that they are there for her, that they see she's tired and scared at times as well. But no, it's about Duncan whaaaaaaa.
Alistair is funny and cute and I had no problems comforting him at first but I grew sick of it later on in the game. He had potential, but I'm too old for a romance like that. It's sweet and adorable but I can only take so much of that
So at times I actually prefered Zevran, despite the cheesy stuff at times, I enjoyed seeing Zevran's conflict, the growth in his character and the change in the relationship. He made my warden laugh, he didn't complicate things and he was loyal, both a friend and a lover, just what she needed.
In the end it's always Kaidan though, even though I have to say I would wish him to laugh more, but we hardly got the chance for that in ME1...and in ME2..well..heh..nothing much to laugh about in the 5 minutes we see him eh?