Off the top of my head:
Emma Caulfield. She was my favorite babe on "Buffy". So funny, so sexy. Too bad she didn't follow Charisma Carpenter and Mercedes McNab and do some naked photo/video shoots (not yet, anyway).
Cobie Smulders -- too bad she made it through "The L Word" without some superhot scenes.
This thread makes me wonder: Do you think any famous actresses have done nude photo shoots and stashed away the photos so they could be sold in future years at very high prices? But then again, superstars like Jennifer Anniston aren't going to be hurting for money in their old age.