CD-ROM games usually come with two files that show up double in EmulationStation. I always edit /etc/emulationstation/es_systems.cfg and remove one of the two extensions so the game is only listed once. I don’t know if anyone else does this, but it makes everything look so much nicer.
For games with multiple discs, you can create a folder and place all of the CDs into that folder. Folders are shown as a different color in the game menu. They can have images attached to them as well. Keeps the PSX folder looking super-clean. 😀 I do the same thing with Commodore 64 as most of the great games have 2+ disks.
I believe optical media is disc, and floppy is disk. Haha