warning: possible spoilers.
I am absolutely in love with Charlie Kaufman's films, ESOTSM being by far my favorite. Michael Gondry's direction also helped to make it an absolute beautiful film, in every sense of the word.
I disagree with sjbrot's view on Eternal Sunshine, but only slightly. I belive that the entire point made by the film was that beautiful things also pass, but that the pain of their leaving is in actuality a part of their beauty. Trying to escape pain through forgetting is to err, because memories, however painful, are only so because they are remnants of both happy and sad times. Joel rushes into the procedure to relieve the sorrow of the end of the relationship, but finds that he values the memories too much to simply throw the entire experience away. Simply, I believe it a fable about accepting fate and treasuring memories.
as for Crash, I had no desire to see the recently released one (it looked like rubbish), but I can strongly reccomend both the David Cronenberg film and the novel by J.G. Ballard. Interestingly, when I searched Amazon to remind myself of the director's name, two of the "plot keywords" options were "leg spreading" and "s&m".