So I just got that one quest where I have to lead someone back to that altar of Bo-whatever and then sacrifice them at the pillar. I have a couple choices on companions but neither of them do I feel ok about slaughtering for that god. Anyone have any recommendations of any companions that would 'deserve' a knife in the back so I can get this quest rolling?

Grab a mercenary. Drunken Huntsman (Whiterun). Another in Candleheath Hall (Windhelm). There's more but only two that came to mind. Or if you did the letter quest in riverrun between the two guys, take Sven. If you did the other guy, I'd keep him for the archery training if you use bows.

Erik "the slayer" in Rorikstead makes a fine choice, if you want to be a sadistic jerk.

Actually I was looking for someone who really deserves it.

The Companions.

I really wish I could have befriended/got his confidence long enough to lead Arcano. He was such a dike. Any other suggestions?

I might be too inclined to recommend Lydia for her "burdens" comment!

But here's the wiki's for followers.

http://www.uesp.net/wiki/Skyrim:Followers

http://elderscrolls.wikia.com/wiki/Follower_%28Skyrim%29