Ravenous will have nothing on the scene that will occur if Robert Carlyle ever finds out you said he was English. He’s from Glasgow…
I 2nd, 3rd, 4th… Braindead. Could only ever watch it once. Christ knows why I bought the damned thing on video - tend to lend it out a lot, gross out my friends. 
DVD with extras, now that’d be nice.
I have absolutely no idea where I remember this from–probably an urban legends book/article/website or something-- but after the uproar over Guinea Pig-Flower of Flesh and Blood, the maker of the film released a Making Of feature to demonstrate exactly how they made the first one. At least this is somewhat substantiated (I can’t cite where I read that) by the fact that you can order both Guinea Pig 1 and the Making Of in a double feature.
I’m not a fan of gore horror, but I think Ilsa, She-Wolf of the SS was rather nasty.
May not be the most gorriest ever but reading this thread had the direct result that a.) I remembered Fulci’s Zombie from seeing it as a kid and b.) Best Buy just got 11.99 of my money and I’ve got me a brand new DVD to watch tonight!
Man Behind the Sun? I’ve only seen clips of it, and I hope never to see the whole thing. It’s about medical experimentation on humans during the Rape of Nanking, and essentially consists of one gruesome “experiment” after another (the clip I saw consisted of a woman who had her arms frozen solid, and then boiling water was poured on them). Another notable scene was an actual cat being eaten alive by rats. The film climaxes with an autopsy of an actual (fresh) cadaver.
An interview with the director. He actually meant to make a serious film, not just a splatterfest.