Collector here:
The games I have are:
APB - This one is an odd one that was pretty awesome in the arcades. Every so many levels you have to make a boss bad guy pull over and then choke him until he confesses at the police station. It is a fun game but not in a competitive game sort of way. First Atari game I got.
Toobin - a fun atari game. It was a blast in the 80s when it came out. Second Atari game I got.
Xybots - first real 3d shooter. Pretty impressive for its time and a lot of fun. Third Atari game I got.
Super Sprint - A lot of fun with 3 players. Very cutthroat. Single player is fun to try to get on internet high score list. There is one guy on the internet who is a god and is way way better than anyone else. Fourth Atari game I got.
Double Play - Unique controls for pitching and hitting. Very novel for at the time. Still fun. It also tracks batting averages and pitching stats for sets of birthdays and initials. Fun record keeping for the time.
World Series- Double play but better. I got a japanese cartridge for the naomi that is a baseball game too.
Tokyo Cop - with motion platform. It was a motion platform for $200. Its fun in a "I am going to drink and drive through traffic to catch a bad guy" sort of way.
I really enjoyed Atari's run on arcade game in the mid to late 80s. The only one that I really want that I don't have is Paperboy but the price on that got up way too high. The game is fun but it is actually better emulated. People forget how much lag was in the controls of the arcade game. It was a lot of fun though. Punch Out is like that too. People remember the game being crazy fun but the controls lag a lot.
Some of the vector games were pretty cool like Gravitar. The screen is drawn with vectors rather than with scanned lines. This allows the images to be really bright because instead of only lighting up a spot on each pass, the game refreshes a spot after each image has been drawn. That is why the bullets in Asteroids are incredibly bright. Playing these kind of games are a treat in a darkroom. You can't do the same with a CRT or LCD monitor. I passed on a nice Gravitar at $1200 that had a good vector monitor. Kind of regret that one.
I got a bunch of pinballs too but they are expensive as fuck compared to arcade machines.
By the way, PI machines suck at accurate emulation. You are better just using an old laptop with mame and a hyperspin frontend.