The first question your salesman should ask is about room size, shape and design (layout).
The second question should be regarding usage (80% home theater / 20% music?)
Don't be skewed by power ratings, pay for quality and listen before you buy.
Good receivers for the money.... Denon, H-K, Yamaha
Good speakers for the money.... Paradigm, Jamo, PSB
A 5.1 system with a nicely matched speaker system will outperform a mis-matched 7.1 system
Are you looking to build towards a nice system and spending more in the near future or spend $500 and be done with it?
-Brian