I think Logan's Run is post-apocalyptic, but it's kinda weird, and doesn't delve into that very much. But I still like it, even if it is cheesey 70's sci-fi. Well, it isn't really thriller, either, it is, as I said, Sci-fi...
Personally, I love the second Mad Max movie, but more for nostalgia's sake than because it was really a good movie.

I wasn't particularly impressed with either Waterworld or Postman, but then, Whatshisname doesn't impress me that often.
12 Monkeys is great. It depends on what type of apocalypse you mean. Not all post-apolcalyptic movies are nuclear holocaust flicks.
Another good one, but weird and kinda freaky, is the City of Lost Children. Similar to Dark City in it's imagery and pure strangeness, it's also a very interesting flick, and worth the watch. I think it's french. I'd say it's more of a dark future kind of flick, rather than post-apocalyptic, but still good.
Here's an interesting list:
http://www.videoscreams.com/PostApocalypticIndex.htm