I generally buy whatever pins I happen to like, but I regularly collect guitar pins from hard rock cafe. Sometimes they have stud backs, but sometimes they have cross bar, so its not easy to put in corkboard, so I used to have a different way of displaying, it is basically a framed fabric display which you can pin them to.
Get a large picture frame (or small, or many small ones, depending on your collection) which you can pick up for cheap. Walmart, craft stores, even going to garage sales and getting old framed paintings, you can tear out the canvas and use the frame.
Try to get a thick frame if you can, because you'll buy a heavy fabric (tried heavy paper, kinda worked, but didn't last for repeated modifications) like a thick felt, or burlap and have to affix it. I'd pick up some old frames, paint them up, and get a fabric that would match with the room (when I was younger - stars patterned fabric looked great)
I streached it across the back of the frame and took a staple gun and stapled it all around. Be sure to get a lot of support in it, I had a lot of weight in metal on some of these pins, it can tear it right out. If you have a lot of pins with crossbars on the backs instead of studs, you'll have to leave a little slack, but still make sure its secure.
Make sure you have good support for the frame too, it can get heavy... and then you'll learn how to patch drywall! Once its all nailed together, pin them all on there in whatever design you chose, hang, and voila!
Sorry meant to be just a suggestion but turned into Arts and Crafts time!
