My favorite dosn't have all that much to do with who's in the scene, as it does with how they got there...seduction is a big turn on with me. And after all the porn i've watched in my life (ok, ok, i'm a perv, and?? lol) Gotta say a few of my favs are :

1) Any scene with Brittney O'Connell
2) One word..."Seka" (And I'm not talkin the coffee either...lol)
3) The "Tabboo" series ( I know some people think this idea of incest is discusting, but if you seperate the idea from the scenes, it's a great movie(s))
4) The Orgy scene in "La Parfume de Mathida"
5) 70's porn is a fav too

Many more I can think of, but that's good for now