As far as an impact I guess it would be Surrender In Paradise with stacy donavan and ginger lynn. The reason being this was the first porn tape that I bought when I was younger, it was in the 80's and I ventured into NYC to pick it up and of course got ripped by one of the camera stores that was selling the tape- I was to innocent to know that I could have walked a little further down the Duece to a porn shop and probably got it cheaper, ah wisdom comes with age I guess. But I must say even at 80.oo plus it was worth it at the time because I got a lot of "use" out of that tape.
As far as what I now watch over and over there are a few that I have on DVDS:
Red Light's Black dicks in white chicks
Almost all of the GAngland and White trash whore series
Service Animals 5 and 10
Rocco in london
Black Craving 8
Up your ass 18
and assorted Aurora Snow titles.