Skinny!
To me, the skinniest chick is the hottest (not ana... over 90 lbs). I say it's a "fetish" since I can get off to a single body part like a matchstick arm, defined clavicle, backbone, jawline, rib outline, lean thigh, flat-chest, thigh gap, etc. Any age from 18-60 and intensity has not changed over the years (something I got off to 15 years ago still does it for me).