Would strongly recommend '64 Williams Heat Wave and '65 Teacher's Pet (the one game that I owned and sold that I probably miss more than any others and that includes Jack's Open, Abra Ca Dabra, Royal Flush, etc.) - just a fun, fast, smooth flowing game.
Also agree with others who said that having a variety of game manufacturers, styles, etc adds to the experience. I would like to get an asymmetrical play field (maybe Flip A Card) - just have to find room. I'm one over my space limit right now!