Making the decision to specialize on a particular classic comp. arch?

I'm wondering if anyone else has this problem. For years and years, I've basically collected anything non-Wintel old-ish (older than ten years) computer-related stuff. I've got quite a few systems which aren't really "rare" like Commodore 64, Radio Shack Cocos & MC-10s, TI-99s, etc. etc. I've also been amassing a collection of DEC PDP and VAX "stuff" which I work on, use, and enjoy on a regular basis. My basement is a mess and I'm starting to think about scaling back by selling or giving away some of the non-DEC common stuff. (I regularily see Commodore 64s on eBay for $20) Is this specializing the right approach? Am I likely going to be kicking myself in fifteen years because I *had* a working Radio Shaft Colour Computer and I eBay-ed it for $10? Also in my mind is the possible demise of analog TV and it may not be possible to find a TV with a composite-input to plug my C64 into in fifteen years if everything (including broadcast) is digital Any thoughts, comments, or opinions? Thomas Dzubin