12 black ultimate pushbuttons (microswitch)
2 ultimate pushbuttons, dunno about color, to work as trackball buttons
Make sure you get the horizontal pushbuttons! You will regret getting the verticals for your main pushbuttons, because they are a pain to wear in, and they just do not feel as good as the horizontal pushbuttons. I'd say it's fine to have vertical pushbuttons for the 4-way joystick, because they are pretty stiff, but if you're gonna be playin hardcore galaga, then I'd go with horizontals for the whole thing.
One thing I wish I had bought the first time round is about 10 extra microswitches for if you accidently bend one so bad that the metal breaks off and you need to replace it, or if something bizarre happens and the metal tabs break off.
Another real quick note is that the pac-man joystick has a VERY small shaft, and a pretty stiff spring, so although it'll feel ackward at first, it will feel good once it's worn in. If Andy Warne had those J-stiks available when I was deciding on a 4-way, I would have more likely gone with that, although I didn't have enough space on my main cabinet to mount the joystick I got. Sorry for incomplete or bizarre sentences, I'm in the middle of Computer Networking, it's wayyyy tooo early, and I can barely function.
About the super joysticks, before you install them, I highly suggest bending the actuators slightly where the round actuator hits them so that they are slightly more sensitive, because it feels wayyyyy better if you install them like that instead of having to wear them in to make them feel sensitive enough.
-Good Luck
-CthulhuLuke