The Rim My Gape scene with Jessica Fiorentino and Melissa Black was a truly great scene, and a perfect example of how much better Jay Sin's older stuff was, compared to most of his newer stuff.
The No Limits scene that was linked to above is actually Janet Peron, but Janet Alfano was in a No Limits scene --
http://legalporno.com/watch/7007/nl_scene_90332 -- which was really good, in spite of Robert Rosenberg's annoying nonstop chatter.
On the other hand, I thought the Hardcore Climax scene was possibly the worst scene out of the dozens I've seen her in, due to a combination of bad camerawork and almost no enthusiasm by her or the guys she was working with.