Any RCA type connector will do for the end of the subwoofer cable. Just get one that looks like it will be easy to add the wire into solidly.

For the wire coming out of the walls, I used wall plates similar to these. Both Parts Express and Monoprice have a big selection to browse through. This one is a bit more pricey but there are cheaper versions of the same. it will accept both banana plugs and bare wire.
I used something similar to this where they all meet the source.


With great power comes Awesome irresponsibility.