I'm going to offer my suggestions by spring boarding off of Green Giant's.
1. If money isn't a big issue, get two U360's. That will cover every type of joystick and have them autoswitch so you will never have to know what a game requires.
Agree. That should be the biggest cp expense because they are just all around great for so many types of games. If you can't afford them get a second job and work it until you can. Only purists scoff at their switching ability.
2. Then get a trackball for golden tee, bowling, and whatever else.
If you don't have the room don't sweat it but a TB is probably the second most useful control on a panel.
3. Spinner is popular for lots of people and take up little space.
I agree. It's something you can safely ditch if money is a concern. But space is no longer an issue with the Turbotwist2 spinner so look into it if you think you may want one.
4. 7 buttons for player using the standard layout seen on these boards. 6 for street fighter and the bottom seventh to make a neogeo layout.
A lot of people do 7, but unless you're a super hard-core Neo-Geo Fighter Fan (e.g. King of Fighters), a 6-button SF layout is sufficient. Nothing wrong with 7 if you have the space though - but don't knock yourself out slapping it the extra button if you barely need it.
5. Then some admin buttons, namely exit and pause. Enter game can be player one, but coin buttons are a nice thing to have.
You don't technically "need" admin buttons depending on your encoder's shift capability (Ultrastick has a built-in one), but some people like them. It's all preference. Not too many though, or you'll end up with Skittles.
6. Pinball flippers on the sides take little space and are easy to do.
You like pinball - put em on. You don't - forget it.
7. If you don't mind spending more cash, get all electric ice buttons from groovygamegear with at least two ledwiz's. Mala and other frontends can automatically light the correct controls in the original colors for every game you have. Once again is great to have since you will never have to ask or answer what the controls for a game are.
I gotta say. I love my LED wiz and Electric Ice buttons, but sometimes I wish I hadn't invested in it. It's going to be great and awesome looking once I get it all set up (lots of little wires, lots of software set-up), but I feel I may have been done already if I didn't put so much thought into how to incorporate the lights into the panel. (BTW: I started working with these back before Mala and other FE's starting implementing their own software).
So I agree - it's really cool. But be prepared to add an extra day's work to your cabinet (and an extra hundred dollars or more). It is worth it - but it's also something that can wait for the upgrade.