only advice i have is dont get a reciever with built in dvd player
i like my stuff seperate and if something breaks im not up shit creek
also, active sub is nice, allows more power to be diverted elsewhere, but its overkill for most of us
if you actually think you will want to upgrade this system to something really nice in the future then just focus on the receiver, its the brain of the operation and the most important part
if i was to do it over again i would bave bought a nice denon or onkyo reciever and then a 6.1 jbl set to go with it, thats like $600, but its damn nice and upgradeable later