I have the following system & just added the Mitsubishi WD-57833 diamond series HDTV: Sony STR-DE945, Bose 10.2 main, JBL S-series center, Polk M2 surround, Cerwin Vega HT-10 powered sub. My room is about 17 x 20 & is not a dedicated home theatre room. My connections are currently running via HDMI cable from the Verizon FIOS box to the tv then via optical & s-video from the tv to the receiver. I am thinking of upgrading to an Onkyo TX-SR 705 to gain 7.1 capability when I upgrade to blu-ray. The speaker system sounds ok but is kind of mismatched/ dated. Would I be able to add speakers that would fit with the current system or would I need to start a speaker system from scratch to complement the Onkyo and gain 7.1? I would be using the system predominately movies (70%) over music.