I'm pretty late to the party on this one, but I thought I would share the good news that you can pair a PS3 controller with your Mac. This allows you to play games using a widely available and (relatively) inexpensive controller.
I enjoy the classic titles available on gog.com but they're kind of a drag to play without some sort of controller. I'm typically a console player so using a traditional mouse & keyboard with some games just felt awkward. A quick search suggested that I could use a PS3 controller without much fuss. Well, it was a bit more fuss than I was expecting so I thought I'd share my experience. I had a few annoying pitfalls but it was pretty easy in hindsight. Here's what I did to get up and running.
Getting ready:
Pairing the controller with your Mac:
Mapping buttons:
You're not out of the woods yet. You'll need a utility to map the buttons on your fancy new controller. I use Controller from VividMachine. A demo version is available on Apple's App Store. For $5 you can download the full version which allows you to create/save profiles for each game you play. It's worth it. Note that you can only download the full version directly from the developer's web site, not the App Store. You'll need to open Controller and choose a profile before starting a game. Just leave the app open while playing.
I like Controller a lot but you'll need to do a little reading first. Be sure to check out the Help link on the developer's web site. Trust me. In particular you'll need to disable Apple's app nap feature for Controller. I was having peculiar behavior until I did this; I kept thinking the button map was lost. Instead, Apple was essentially turning off Controller while I played my game.
Additional reading: