Hard to believe, but cats (some cats anyway) love to eat avacado. It helps to build a soft coat, and helps to prevent skin dryness.
I appreciate the information. It's confusing -- the following sites suggest avocado is ok for cats:
http://www.arcatapet.com/item.cfm?cat=12488 (which uses it in their AvoDerm Natural Chicken & Herring Formula Kitten and Adult Cat Food)
http://www.petstruly.com/dasuquin-cat-84.html (which includes it in a nutritional supplement for cats)
. . . but lots of other sites do say that it's poisonous. I will ask my vet.