I don't mean the "best" companions as far as combat usefulness. Or even ones that fit the style of your gameplay. I mean strictly because of the voice work for them.
While revisiting the wastes and walking every square inch of them before the final save in New Vegas, as I like to do in any FO game (and afterwards in the case of FO2), I have Raul in tow because... well... Danny Trejo ("Lowly dog!"). Even if he does have irrational anger towards moving your feet.
I have absolutely no need for him, and I've been traveling solo up until this point. My character was initially a mechanical and science! brainiac, and at this point is 20 skill points away from having everything maxed. He serves no purpose, other than being Danny Trejo, and I will sacrifice my last Super-Stim for him in the middle of a pack of Deathclaws if need be, as useless as he is.
I guess I would also ask who don't you like simply because of the voice actor? I'm actually trying to think of one, but it always boils down to the writing when it comes to characters I just can't stand to have with me, and less the voice actor delivering them. Like Jack or Kaliyo. They're basically the same "tough girl" character that sounds ridiculously forced and tryhard, and they both annoy the crap out of me. I'm reasonably sure the same person at Bioware conceived both of them.
Anyway... Danny Trejo!