I think that if you don't support a substantial amount of a religion's doctrines, then you shouldn't call yourself a member of that church. It's a disservice to yourself and to the religion.
Catholics who enjoy the ceremony but not the restrictions can always join us Episcopalians!
Seriously though, you can't always get what you want. If you like some elements of the Catholic Church, but disagree on such huge issues as homosexuality, divorce, birth control, premarital sex, female priests - I just don't see how you can reconcile that and still call yourself a Catholic with a straight face.
I have never been a Catholic, and have no desire to be, so of course it's an easy choice for me. For people who were raised in that faith, and still want to follow it, even when their personal feelings are so far from church doctrine - well again, You Can't Always Get What You Want.