Speaker suggestions

LeftCoast

I have RT5000 that I'm planning to use in my living room. I'm hoping to get a deal on a Pioneer Elite AVR during the holidays. If I want to add speakers for a 7.1 or higher set up, what speakers would match well with the RT5000's I already have? Or should I just use the speakers I already have, and leave it at that? (I will have a more elaborate set up in a separate HT room.)

Mystery

Rear surrounds are not as critical as fronts so anything in RT line should work.