How you tell is you listen to them. Unfortunately this is almost impossible at Circuit Sh-City.
I would recomend that you spend a little More, and buy a good pair of B&W's and a receiver (should be around $1200). Then wait and save and buy a sub. Then wait and Buy a pair of Tower B&W's and a Center Channel.
All in all, I think the system should cost a total of $2,500. I would not be happy with any system at a lower price. I care more for sound quality then audio level, and at $1,000 for a 5.1 speaker receiver combo, you will be lucky if you could get any quality at all.
I personally would recommend spending the most money on your Speakers then any other peace of equipment. Also 7.1 systems are a waste of money and resources, especially for the prices your talking about. Any sub $1,000 combo that includes a 7.1 system is an obvious attempt at targetting the ignorant.
I can just imagine the consumer saying: "Wow, 7 speakers MUST be better then 5! Ill TAKE it..."! Or worst, the poor Circuit City Employee who doesnt even know the word "Ohm", telling the consumer "7 speaker systems are the BEST, I would buy this system!"
BTW; I spent 2 hours in the Circuit Sh-City store explaining why I needed 4Ohm front powered receiver, and educating him on what a Ohm is... Then waiting as they look up all the documentation of the receivers to find one.
I would recomend the 2 speaker aproach and spit out a bit more cash. I would also NOT recommend consumer level speakers, and buy more Audiophile level equipment. Dont be afraid of used high end speakers. If the drivers die, you can always buy replacement drivers.
Note: If you cant buy replacement speaker drivers, then its not high end... Its consumer grade.