Initially I bought the Monoprice banana plugs (pack of 10) and they worked well enough, since I always power off my unit. But I didn't like the length of the barrels, my 12AWG wire sleeve wouldn't go in all the way, leaving about 3/8 of an inch exposed internally and the fit wasn't that snug connected to my Yamaha AVR's speaker connections.
Next I bought a pack of the Sewell Direct SW-29863-12 Deadbolt Banana Plugs at Amazon, that markw mentioned, and they've been my speaker connectors of choice ever since. Of course a month later somebody on Craig's List was selling the 12 pair pack for $15.
I purchased 3 packs and haven't looked back since.