there are some decent sounding sets of a reciever / 5 speaker combo in the mid hundreds range.
if you were an audiophile, well that's a different story.
if this is for multimedia (watching DVD's in full THX and the like) thats even a different story.
i'd look into something like
THIS though something like
THIS has more features and probably sounds better.
the biggest thing is no matter what it sounds like in the store it will sound NOTHING like that in the acoustics of your own home.
don't buy from best buy, use them as a guide. then go to a local audiophile store witha good reputation, and see about a "trial" period, where if the sound in your home is not satisfactory in 30 days, you can get a ful refund on a different system.
the problem withe the packaged systems though are the speakers. you kind of are stuck with them if they dont sound good, yes you can hook up others, but it's wasteful money.
if you don't like the sound you have to return the whole system. which is no necessarilly bad, but might be a pain to hook all that stuff up.
simple answer is there is no easy answer to your question LOL