SHURIKEN ON DISPLAY - Museums, Libraries, Public Displays
I will try to list collections of shuriken on display in public places, such as museums, libraries and other locations

Koga Ninja Museum, Koga City, Shiga Prefecture. Japan.
These pics were kindly sent to me by Takeshi Yoshizaki and Danny Fletcher. According to one source, Fujita Seiko, author of "Zukai Shurikenjutsu", and one of the last Koga lineage holders, donated all his Ninjutsu related possessions, including shuriken, to this museum, shortly before his death.

Iga-Ueno Ninja museum, Ueno City, Mie Prefecture, Japan.

Togakushi Ninja Village Museum, Nagano Prefecture, Japan.
Apparently Masaaki Hatsumi Sensei, 34th headmaster of Togakure Ryu donated many weapons from his personal collection to this museum.
Here are some pics from http://www.skydancers.com/japan/10togakushi8.html and http://www.ninjamura.com/