I thought as long as the foundational things were covered - family values, commitment to the marriage, intelligence, honesty and respect towards each other, and a sense of fun that everything else wasn't really going to make much difference. Do we REALLY have to like the same music? Do I really HAVE to like sports as much as he does?
Is it really necessary to have a lot of things in common with your mate? If not, which things ARE important?
This is my feeling. For my husband and I, the big things - how we view the world, relationships, family, etc., are in snyc (but not precisely the same)... I know that he is the one that I trust most with my heart, my life, my sanity

... Other than that, we are VERY different. Our view on religion is not the same (I have a more open, esoteric stance) - which is not as important, I don't think, since we are not in child-bearing years. We have activities that we have in common and both enjoy, but we also allow each other space to be unique and enjoy things that the other may not - without feeling that we have to share every single thing to be a happy couple.
It really depends on the individuals involved. Some couples want to dress alike

and everything... others love their individuality. For US, coming together on the big issues and respecting/honoring each other's differences has kept us going strong and looking forward to spending our lives together (people STILL ask us how long we've been married, thinking we are newlyweds).