Other cats. I'm also in the need of "hook-ups" for more cat nip.
Cat Power
Heathcliff, Felix the Cat, and any of the Meow Mix Commercials.
The Cat in the Hat by Dr. Seuss, Hemingway's Cats: An Illustrated Biography by Hilary Hemingway, and Who Let the Dogs Out? by H.B. Homzie and Matt Phillips (I still haven't figured out who did. If you know they deserved to be scratched.)