I'm setting up my servers to only allow logins via public key and
turning off password access. What I want to know is, how do I manage
all of the keys? The only thing that has worked so far is to have one
key for all of the servers.

Second, if there is a way to have multiple keys, when I remotely login
with my laptop, I'd like to have them on some kind of media separate
from the laptop. Any suggestions on how to do this?