Well since the OP included the "in her prime" caveat for some selections, I'll do the same for mine.
Jenna Jameson
Jill Kelly
Chasey Lain
Nikki Tyler
Briana Banks
Tera Patrick
Sylvia Saint
Eva Angelina
Sasha Grey
Tori Black
I'm stunned at how easy that was to whittle it down to ten from the list of "who have I been psychotically infatuated with over the last 15 years." The shortlist was only 12, and I eliminated Racquel Darrian and Janine Lindemulder on the basis that while I've certainly spent a lot of time enjoying their work, neither ever really had a spell that I can think of where they were my "current favourite" whereas each of the ten chosen have. With a minute or two of reflection I think Jenna Haze fits into that category too.
From today's active crop, I gave serious consideration to Kagney Linn Karter, Alexis Texas, Rachel Starr and Christy Mack. But for the ultimate fantasy scenario, I had to pick my ten favourites ever ever ever. And they were surprisingly easy to pick.