I have an Onkyo 606 and currently have a 5.1 setup: - Front Speakers are Polk RTi38 - Center Speaker is Polk csi30 - Surround Speakers are Polk FXi30 - Klipsh Sub I'm am contemplating whether I should purchase 2 additional rear speakers to upgrade to a 7.1 setup. If I decide to do this, any suggestions on the 2 additional speakers? Are there certain "rear" speakers that I should specifically purchase or do front speakers also work as rear speakers? The reason why I'm asking is because I was thinking about the possibility of moving my front speakers to the rear and buying floor standing speakers for the front. Does this make any sense? I've never seen speakers that are specifically identified as "rear" speakers (despite that the speakers that I currently own are specifically identified as "front," "center," and "surround" speakers).