After making Erik the Slayer my steward, he won't say anything other than telling me I can hire him for free, or his regular dialogue (if he is currently a follower). Is this normal for a steward or is it a bug?

There is a bug with Erik as steward:

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

I would reload a previous save if you can. He's a great follower though!

I have a save before I made him my steward so I guess I can reload. Who else would be a good choice for a steward?

I just posted this link in another thread, it has the list of followers that can be made stewards and possible bugs some may have.

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

I have Golldir as steward, though I don't recommend him, he wanders away a lot. I have Faendal for another, I like him and he does well and stays where he is supposed to be, and Roggi Knotbeard, who is also working out well. I never have my stewards furnish anything except the entryway, so not sure how well any of these would do.

Also, if you have vanilla houses and don't care if one is missing a housecarl, they usually make good stewards.