What kind of speaker makes a good rear channel (for 6.1)? Would I buy something like a 2nd center channel speaker that just goes in the back of the room? Would I buy something like one solitary satellite speaker? One 2-way or 3-way bookshelf speaker? In other words, what type of speaker should the rear channel be? Also, if you have any specific recommendations, I can check out the website you found it at. I would like to stay under $100, if possible.