So, who do you guys think are the most well known pornstars (past or present)? I don't just mean most popular now but where even a casual porn fan may have heard of them.

Some I'd venture to guess, (in no particular order)
Ron Jeremy
John Holmes
Linda Lovelace
Traci Lords
Jenna Jameson

Who am I missing?

Peter North
Marc Wallice...for giving his co-actors HIV
Ginger Lynn

I don´t think that North and Wallice are known OUTSIDE porn.

But I think the general people knows Belladonna quite well.

I'd include Marilyn Chambers.

Seymore Butts because of his program on Showtime .

As begrudging as it is for me to do we have to add Mary Carey.

Mary Carey, the most overhyped, most boring pornstar on planet earth. She is a dolly bird and fucking dire!
There are only three well-known pornstars that I can think of that have commanded massive global attention. That's Ron Jeremy, Linda Lovelace, and John Holmes. The remainder are popular, but not as famous as those three - strangely two of whom are dead.
LB.

Jenna Jamesson
Janine
Taylor Rain
, hhmm

I've been watching Tom Byron all my life, it seems. Everyone I know has heard of him.