i found that polk audio you can get in many online sites cheap even neweggs got them.
there a good speaker for the money so if you get a chance to listen to them i think you will agree.
recievers dont go crazy on spending to much some have to many bell and wistles.
onkyo, yamaha they make nice recivers.
cables same here dont go crazy on hdmi or digital cables. but speaker cables you will here a differents. i use audioquest dont get suckered into monster cable i found it mutes the sound compared to audioquest.
after you got your system pick out and installed save up for a good subwoofer. you can have a great sounding system and install a low end sub and ruin it badly.
so you got some listing to do dont let anyone tell you this sound better. you be the judge of that, trust your ears. happy hunting and good luck
ps if your left and right speaker use 6'' and a 1'' make sure the center speaker uses the same size speakers. the back speaker it doesnt matter that much.