I connect my HiFi speakers up with Banana plugs. The amplifier ends have DIN plugs on though.

I use the generic ones from Rapid/RS/CPC/whoever; the same ones I use for multimeters, bench power supplies, etc.

I'd suggest getting the ones with screw terminals though rather than solderable ones. If you wish to solder them, you will need a rather powerful soldering iron as a 4mm banana plug is quite a big lump of metal and will suck the heat right out of the iron.