If you didn't know about them already here's a few sites we use for cables, wires and stuff.
http://www.monoprice.com/http://www.monoprice.com/
http://www.parts-express.com/
http://www.bluejeanscable.com/
I think the Beta 20's are kind of under-rated. Excellent all-around speakers. Cherry models are gorgeous. You didn't mention a center channel. Beta 20's can handle a 50hz crossover in most situations so a receiver with a single crossover setting (Pioneer, Yamaha) shouldn't be a problem.
For...