The "norm" for me is twofold ;

Sentimental Value - Games I remember from when I was a child.

Rare games - Any manufacturer. Anything interesting.

I do stick to Bally SS as this is my favorite era and favorite manufacturer. I have spent years collecting my Ballys. Dad gave me Paragon and KISS. I then collected Fathom, Medusa, Viking, Centaur, EBD, Flash Gordon and Vector. I had to sell the Space Invaders as it scared my son when he was younger. I do own Haunted House, Spirit and Black Hole. They are all games I used to play in the city in 1982-83. Flight 2000 and Freefall are rare Sterns that are players.

EMs - I do like Gottliebs and Williams. But again, Bally EMs are my favorite. Shortly, I will be adding HUO Fireball, 4 Million BC, Captain Fantastic, HUO Nip It and Air Aces. This mini collection of EMs is better than any Gottliebs or Williams. They will sit next to my Wizard and Mariner. Gottlieb Spirit of 76 is my favorite EM. I've kept that game in the collection.

DMDs - CV is a keeper and is by far the best DMD ever made. I might add Scared Stiff down the track.

I would like to add rare Bally/Midways such as Atlantis and Transporter.