Very interesting how everyone has such vastly differing opinons. I didn't used to think that sex was so important, until I went without for many years. Suddenly, it became obvious that the lack of physical intimacy caused the breakdown of just about everything else. I believe that Tao's list is not so much as ranked as it should be equal parts of the whole.
Without love, the sex is, as Duffy said, "bumping uglies". Without sex, the love will fade. Without Intellegence, humor, conversation and hobbies will be hard to share. So I suppose it is all 100% important...
I suppose the rank method is throwing everyone off as it really isn't something that can be ranked accross the board.