I'm generally lousy with names and too lazy to look up spelling so here goes:

Viggio Mortensen (Hidalgo, Lord of the Rings)
William Shatner (That "Old guy" who used to be in the original Star Trek :::said tongue in cheek::
Alyssa Milano
Holly Marie Combs (I read an article about them both riding up in Burbank near my brother's house)
Raquel Welch (actually her brother-in-law used to breed appys - She bought him a leopard appy - And I got to meet her and talk to her for about 30 mins... really nice person!)
Richard Gere (Appys)
Robert Redford (Palominos)
Dennis Quaid (Okay, this one kinda tweeked my brain)
Christie Brinkley (Champion Cutting Horses)
Hillary Duff