Gotta agree with Franko on that one.  My "collection" is merely a collection by merit of having more than one.  In general, I use a Windows laptop because that it what I support in my day-to-day business.  But my hobby activities revolve around a rotating schedule in front of my various Amigas, Commodore 128D, and TI-99/4A systems.  And I am working to add an Atari 800XL to that mix, once I open up some time in my schedule.  Right now I am busy fortifying my TI system and rewriting some of my old games.
In terms of what I have in the closet, I do have several Amigas which are for parts purposes, and I am working to trim that down.  Ditto on Commodore 64 stuff.  I keep spare Amiga 500s, a couple of C64s and C128s, and TI-99/4As on-hand, just in case.
Specifically relating to the Amiga, I suppose my "collection" started in 1993 when I picked up my first spare A500 unit, or 1994 when I picked up an A1000 to work in concert with my A500.  I was forced to use my A1000 as my primary system for a short period when my 500 pooped and I had no spare mobo available.  Now it is sitting in a box awaiting the installation of the Fast-PAL kit.
Feh.