need some input on new system

hello all, i'm going to start to put together a new system.i've got everything pretty much narrowed down.the receiver i'm looking at is a sony str-da7100es, its rated at 170watts x 7.the 2 front speakers i'm looking at are the Polk Audio RTi12 rated at 500w.heres the question i'm planning on buying a outlaw amp, i can't decide to get the 200x7 or just get 2 mono amps at 200w a piece.i would like to get 2 more of the polks for the surrounds but i don't think they should be half the size as the fronts,i'm thinking of maybe letting the receiver powering them?one more thing the center speaker i'm looking at is the Polk Audio LSiC rated up to 200w.if i was to just put 2 amps on my fronts and run them @300-370w would that drown out my center?should i purchase 2 centers?as for a sub and the 2 back surrounds for 7.1 i think i'll wait,i may not need a sub and 7.1 hasn't really caught on yet.sorry for the long post but i just wanted to get the info out.