Personally, I've never worn jewelry.  Jewelry is for people, if you ask me.  And if you're a real cat lover, sooner or later you're gonna want some cat jewelry.  Here's my suggestions of where you can shop online.

JustCatJewelry.Com -- not the best designed site, but lots of great
         cat jewelry, including earrings, braces, charms, and watches
CollectiblesToday.Com -- cute stuff!
BestAnimalJewelry.Com -- just ignore the dog trinkets
CatsPlay.Com -- fancy collars for your cat
Gold and Silver Cat Jewelry - cat-themed jewelry galore!