This morning I installed a pair of Polk Atrium 45's for my back patio. Purchased from Amazon for $105 (open box unit). I used 14AWG wire from Monoprice.
Very solid construction. Hefty weight, good mounting brackets, simple to install--minus running the wire. They look beautiful and discrete.
Sound is incredible! Clean, powerful, and dynamic. I'm amazed at the level of output these small speakers produce. I can hear them throughout my entire backyard, which is a little less than a 1/4 acre.
Some reviews have commented on the lack of bass. I don't expect much outside, but installed under the eaves they're perfect. Tight bass.
Overall, I highly recommend the Polk Atrium's. I'm very pleased.