Mei-ling and Syoaran
Pros
1. They live close together
2. Their families are obviously close
That's about all '^_^
Cons
1. Syoaran doesn't love her back
2. Mei-ling is a bit too protective if you ask me
3. Syoaran isn't the happiest person around Mei-ling....
There is no Mei-ling in the Manga.