I have always thought the 3" CD was quite unique, especially the Japanese version as they are packaged in a snap pack style container. It is fun to track them down in mint condition and unsnapped! I will post my collection according to artist. Also just for all of you fanatics concerning keeping your Japanese 3" CD's in mint condition and stored properly, I recommend two things:
Store them in their resealable plastic sleeves, which can be ordered here from this AMAZING Japanese website run by Ben, whom has the most incredibly selection of Japanese goods at TOKYO MUSIC JAPAN
Also I've managed to find the perfect containers to store your collection in and keep them proudly on display! It is a clear AMAC box designed by the AMAC Plastic Products Corporation which can be ordered here: It is the perfect fit for the 3" CD's and comfortably holds approximately 20 in their plastic sleeves! You can purchase them at The Container Store here:
You will want to purchase the item #60500 which is 4" sq. x 7-1/4" h.
Here is an example: