I'm building an entry level home theatre system(hts). I want to spend no more than $500 on speakers to start. First off I have a Harmon Kardon AVR325. From what I've read it's better to build a hts with individual components than to buy a hts in a box. Is that true for speakers. I've seen speaker packaged sets but I'm not sure about them. Should I start by buying a couple of tower speakers then purchase a center speaker and then a subwoofer. I heard some Cambridge Tower speakers with the subwoofer built. They sounded good but I don't remember the cost.