These days, on the odd occasion that I have someone over or when I am discussing my setup with someone, I will mention that I have five subs. Invariably, they will make a comment about how my home theatre surround sound must sound awesome. I then tell them that actually only one sub is for the home theatre and the other four are for listening to music. They are dumbfounded until I explain about how things actually work.
If you like one sub, you will love four.