It depends on what you define as disgusting and shocking.
For disgusting it's any of the Hostel films (slash horror doesn't do it for me at all). Also Centipede 2, only seen clips and not my cup of tea (have seen the 1st film and that was ok.. was a very dark humour horror, reminded me a bit of an updated hammor horror movie).
For shocking then a film called The Strangers. I have managed to watch maybe 15mins then I get so freaked out I can't watch anymore ...
Also shocking (but one of my ALL time fav films) the Poughkeepsie tapes.