[Audioholic123]

  Sorry about quoting myself but I wanted to explain that this was intended to be somewhat humorous. I should have put a smiley at the end. I hope no one was offended.
I myself have had so many speakers at one time my den looked like the Grateful Dead's wall of sound.

I think you hit upon an important point.

 

[SuburbanMe]

  A similar, if not equivalent, question would be one of the Collector vs. the User. I have two headphones (well, amongst others) that sound similar and make sound similarly, and I use both. At this point, I would not buy a headphone primarily to possess that headphone for its historic or aesthetic value.
 
So, a selection would be any number as long as they are all primarily for use, and a collection would include pieces which were primarily there for some other reason than use.   

 
I think this is a great point right here.
 
Collection kind of implies you own something for some kind of value over use. The value can change from historical, sentimental, or just wanting to own something from all the manufacturers. But in the end I think the main difference would be owning something just to own, or owning something to use it.