speaker wires from $0.99 store works great.dont buy the hard copper wire that you can bend.those are hart to work with..
Actually, on the contrary, very easy to work with. My cabinet is done in solid wire. There isn't much stranded in it.
Solid copper is great for soldering.
Now, if you think the wires are going to move alot, you don't want solid then, you want stranded so you have flex. But in many cabinet the wires in the cp aren't going to be moving much:)