My cab probably won't have a spinner, at least not for my first control panel.
I was sold on a trackball after playing Golden Tee Golf and World Class Bowling for a few minutes. But I was also able to get my trackball for only $17 (inc. shipping) off of eBay, which made the prospect much more enticing. I was able to hack a mouse I already had (with some help from my dad), so putting a trackball on my cab will work out quite nicely.
I was sold on a dedicated 4-way joystick, because I'm gonna use Happ Competition joysticks for players 1 and 2, and many people I have over will want to play old classics like Donkey Kong and Pac-Man, so I eventually decided to order a Happ Universal joystick (switchable 45 degree rotation is handy for the occasional Q*Bert fanatic I might have over). It was another $15 plus the cost of 2 matching buttons (which I've yet to order), but it's a small price for the ammount of versitility it'll add to my control panel.
But as for a spinner, they seem quite foriegn to me. I'd never played a Spinner game in all the years I'd been to the arcades at roller rinks, bowling alleys, and arcades. I downloaded Tempest for my PC, and I'd imagine the game would play much differently if I were using a spinner instead of a mouse. But I have trouble imagining it being worth the investment. If I want a spinner with nice smooth spin, I could go to either Oscar Controls or Slickstick for their tornado spinner, but both seem very expensive to me. The Tornado certainly sounds like the Hercules of spinners, but it's $90. I don't want to spend $90 on a device for games I am not terribly nostalgic about. Oscar controls' best spinners are a bit more reasonable, but they're still $50-$60 bucks a pop.
And when it comes to controls, I want to make sure I'm getting the best that I can without spending a fortune, or not bother. With the trackball I was lucky to get one in good enough condition that it only took a thorough cleaning to make it cabinet-ready. Otherwise I would have been in quite a jam, and might not have even gotten a trackball until I could find one at an affordable price. Also, since I'm using a mouse hack to interface the trackball with my computer, I'd either A) have the spinner share a connection with one of the Trackball's axises on the mouse PCB, or B) spend even more money on an Opti-Pac. Niether option looks so good to me, so I think I'm going to just opt to not have a spinner.
However, you always have the option of having a second control panel. I wouldn't mind eventually making a control panel with a spinner and 8-Way trigger grip joystick so I can play a game of Tron and a little tempest on the side. Having a setup like this would do 2 handy things for me. 1) it would save me money in the short run, and 2) it would keep my control panel from becoming overly crowded. Also, I know that there's not room on my 1st panel for an 8-way trigger grip, so I'm probably best off saving the spinner for when I have a control panel that does.