Wow, there has been a lot of good information from all to help me clear this up. Alan's article hit the nail on the head with this issue and I am completely convinced. The first link was also very good, but quite technical. The "flabby", "loose" bass myth is almost as bad as the need for ultra expensive cables (speaker cable, HDMI, etc.) myth. It seems that to choose the correct sub you just have to narrow it down to good sub companies like: Axiom, Hsu, Outlaw, SVS, etc. Once you settle on the brand just make sure that you choose one (or preferably two) large enough to fill your listening area. That's it.