Always though Flesh Gordon was pretty good, too.

Another was Murder on the Orient X-press. As I recall (and it's been a lot of years ago), the movie was pretty well made with more of a story line than most.

Not porn, but the nudist film "Julie" was good. Dealt with a young lady who had to do a college research paper on the nudist lifestyle with the help (??) of her boyfriend. Very nicely done with some humor and cute scenes.

Also saw a bi-sexual film called Miss Kitty's Litter which was pretty good. I think about three or four mini-stories all taking place in an "old west" setting. Surprisingly elaborate scenes.