The small plate holder that are make to display small china plates work real well. Some of the discs don't have a straight lip on the inside and will slip off a nail or push pin (for example, a roc plus). On a real soft or floppy disc, you may have to stretch the spring a little bit, but the plate holders rap around the disc and hold it so it can't fall.
I use these hooks called command brand damage free hanging. They are metal hooks that are attached to plastic and have double sided tape on the backs. They work really good and dont mess up the wall if you want to move them around.
Like most everyone else...I use push pins, but one disc seems to keep falling off. It's a tournament disc with a diabolical figure on the surface. I just write it off as a diabolical disc and put it back up on the pin and wait until next time.
I asked my wife what she thought about this... she said not to worry about it too much... that if i attempt to hang a disc on the wall, there will be no discs to hang... she said something else, but i was furiously trying to patch the hole....