Chadnliz and Rok2id, one answer to your question is that if you are listening to acoustically produced music, the vast majority of musicians will tell you that subs simply don't sound natural, no matter how well integrated. I have yet to hear one that does, myself. So for us, it is full-range floorstanders, and the subs are not an option, unless we want them for a separate home theater system. There is extremely little acoustic music that goes below 40hZ, let alone 20, so unless you want to accurately reproduce say the lowest organ pipe, a sub is simply not necessary, and is in fact quite detrimental to timbre. A whole bunch of folks here don't like that sort of talk, though... :)
