I've been into collecting since 1996 and I started by targeting what I grew up with - 2600, INTV and CV - and what I still had in my possession - NES, Atari 2600, TI 994/a.
What started as a small nostalgia trip turned into a full-blown hobby that is very enjoyable! I lost a few years (2003-2005) due to divorce and more recently for a family illness. I'm no longer actively collecting since I've found that even my "play" money needs to be for the family first at this point in my life so my collections have shrunk and ground down to a near standstill.
At the height of my collection I had an entire gaming apartment set up with roughly 25 systems across 2 rooms(double parlor), a computer network in a 3rd(1st bedroom), a ton of board games(kitchen) and a small room set up with a library(2nd bedroom). I gotta have my books.
I also helped plan a couple of the old PhillyClassic conventions under David and Chuck. Had some good times with this hobby and the great people in it!
Now I'm in a decent-sized apartment with a girlfriend and her daughter so I have to keep my collection on the smaller side. I'm always looking for space-saving options though like multicarts, loaders and such. I also have an X-Arcade emulation station set up.
Aaaah, happiness is gaming.