Raul. Didn't have to think about it, I love his comments, his perk is really useful, his story is one of my favorites (especially the gunslinger ending), Danny Trejo rocks, and he's available early on. I love them all, really, but Raul is my favorite. Of the DLC companions I'd have to put Joshua Graham at the top but most of that has to go to Keith Szarabajka's perfect performance for his voice acting, which is in my top ten of all time. Actually when I put it that way I guess I shouldn't count him and instead go for Dog/God.