Vintage IC collecting began around 1998. There are now hundreds of very active collectors and museums around the world. I have been collecting since at least 1998. I use to collect coins, but that can be a bit crazy. What I enjoy about IC's is the ENTIRE history of them is contained in just over 40 years. Some of the 1970's designs are truly amazing from an engineering point of view, and often from a packaging point of view (white ceramic/gold etc, vs the 'boring' black plastic. I also work with visual6502 which has been building silicon level emulators for the 6502 and others, its amazing how much variance the die has from the datasheet (errata and undocumented instructions to name a few).

There are also those who buy old ICs to restore vintage computers (Apple 1's being popular now, in memorial of Steve Jobs). The proper 6502 from them can fetch $2000. I have sold some spares to companies trying to fix legacy equipment that is 'irreplaceable.' The amount of IC's we would call vintage, that are still in use is staggering. Keeping these systems running has spawned an entire industry, including remaking the original ICs, REI (which does so with original masks) and innovASIC (which used ASICs to replicate them) are 2 companies whose entire being is based on legacy.

Another benefit of collecting vintage IC's is they don't take up uch room (ok except Slot 2 Xeons lol)
A few other electronics related collection hobbies that have grown tremendously int he last few years:
Tubes (namely Nixie type and other display technology)
OLD transistors (1950s and 60s)
Core memory
Databooks (some of these are pretty handy for the old stuff, especially the old IC Masters)

If ya have extra stuff hanging around, let me know. My museum likely could use it (and save it from becoming a tie tack (or belt bucle as I recently found a engineering sample Pentium Pro mounted to lol)
-John
www.cpushack.com