Jason,
I have a pair of Polk Atrium 50's in a covered patio that sound pretty good. Since the patio roof is an extension of the house roof I hardwired them to my Yamaha RX-V1800 which handles the second set of speakers just fine; obviously you're not going to get the same sound outside that you do inside your home but not bad. Polk's list price is around $240/pair but I picked them up on Amazon for $200.
It's interesting that you mentioned the Best Buy wireless kit. I use that with my Aperions. My surrounds are 5B's. Their kit (Rocketfish) was easy to install and it works great (although my Yamaha thinks those surrounds are twice as far away as they really are - lag from the wireless - but that's fine, it compensates for it). Bear in mind that the range is 100 feet and you need a power outlet at both ends. I also doubt that the receiver should be used outdoors. You'd also need to make sure that range is still good if you're going from inside your house to another building. I'd think there would be issues there.
Joe
If you can't have fun doing it, it's probably not worth doing.