OK, lets see the score:
Color Vectors: Tempest
B&W Vectors: Asteroids
B&W Games: Tank II
Golden Age Classics:Berzerk, Donkey Kong, Food Fight, Burgertime, Frogger, Ms. Pac, Missile Command, Punch Out, Root Beer Trapper, Tron, Zaxxon (12)
Nintendo Games: DK, JR, 3, Popeye, Mario, P.O. (6)
Silver Age Classics: Gauntlet II, RoboCop
Pinballs: Time Warp
The court has seen enough. I am prepared to render an opinion.
First let me compliment you on an excellent collection of games as well as the act of opening it to public. That being said, on the breakdown, its easy to see a blatant absence of Shooters. As most arcades should lean towards the golden age, Galaga is an easy choice, but the selection of Space Invaders would also fill the bill, be another B&W game and another cool cab to boot. Gaplus is the sequel to galaga and is a better game if you aren't a fan of Galaga's repetitive nature. R-Type, or Gradius would be a nice Hor. shooter and that would fit into the Silver Age. Raiden would be a good 90s shootemup.
I also see a lack of jamma games. If you are looking for mass apeal, a generic 4 pl. Konami Cab could be used for Simpsons, X-men, and Turtles. A nice generic 3 button Jamma HS-5 Dynamo could be used for Sega System 16 games like Altered beast, Shinobi, and Golden Ax with a converter as well as a plethora of other beatemups and shootemups.
I think you could use a fight game or 2 to represent the 90s accurately. MKII is my choice, but a nice 6 button HS-5 running a CPS-II board could be used to easily swap out between Super Street Fighter, SF Alphas, Marvels fighting lineup, and Vampire Saviour lot. Thats a lot of diversity and an easy swap.
I think the pin collection could be a little more robust. Your collection is primarly 80s and to keep cost down you should stick with that theme. Good choices would be Pinbot, Black Knight, and Funhouse, although some cheaper DMD titles might be the more bang for the buck. I'm thinking Star Wars by DE, Fishtales is fairly fun and reasonable, maybe Jurassic
Park, or Tales from the Crypt.
I also think you need at least one additional color vector as well as another B&W. For the color, I'm thinking Star Wars or Black Widow. Battlezone, or Red Baron for the B&W. Any of the color vectors would work but SW has that mass appeal and isn't as ridiculous as Maj. Havoc or Quantum. And Space Duel is just a color version of Asteroids.
I wouldn't want to condemn any collector for their choices since a collection is statement about personal preferences, but assuming your collection isn't made up of titles you can't stand to get rid of and space may be a restriction, here are the titles, I would look at cutting from the list:
Kangaroo (most don't care for it from what I have heard)
DK3 and Popeye (the first for the reason above and the second due to the difficulty)
Foodfight (maybe)
Nibbler (maybe)
Vindicators (looks cool but I hear its not a great title)
Vapor Trx (a twin racing game is awesome, but I think there are much stronger titles out there-Hyrdro thunder, Daytona, Rush, Sega GT, Cruisin USA...)
Other random titles I think you need would be:
Centipede, with new art since women are attracted to this game and Ms Pac
Almost any Universal dedicated game for the cab artwork
A Williams Multi game since I'm not personally a fan but they should be represented in the line up. If you can only pick one dedicated, Robotron, Defender, or Sinistar
Taito could use a little more love. Zoo Keeper, Qix, Elevator Action, or Jungle Hunt maybe.
I also think a shooting game would be awesome in the line up. Personal favorites are Zombie Revenge, Space Gun, and the Jurassic park Sit Down. Newer titles are Area 51, Maximum force, and Carnevil. Games with mass appeal are: T2, Revolution X, and Lethal Enforcers 2.
I hope thats the kind of suggestions you were looking for, and I hope none of the suggestions offend. It was not the intentions. Good luck with your grand opening.