I have a Onkyo Tx-nr686 i bought last year and i am currently running a old set of sony book shelf speakers and a center channel that are 100 watts and 8 ohms in a 5 speaker set up. I am looking to finally upgrade my speakers. I was hoping to be able to do tower speakers for the fronts and the bookshelf ones in the back with a new center channel. But i don't want to throw away money if my system isn't powerful enough to get the potential benefits. My question is what wattage and ohm ratting should i be looking for? Not looking to spend a fortune on the speakers but i have looked at the polk t series and monitor series 2 , the sony core series and the klipsch if i can find the right sale. Any help would be appropriated. Thank you in advance.