There are lots and lots of terrific ways to keep household info organized out there, but as far as paint colors in my home, this one is easiest for me! I keep my idea paint chips separately, but for paint I've actually used I simply tape them into a file folder and label with the room I used it in. I like it because I can see them grouped together, they are easy to find, and it doesn't take up a lot of space in my file drawers.
Quick, easy, and effective...that's how I roll. :)
Have a terrific day!