I try not to be to limiting in whom I believe should be a couple. Obviously, some matches are better than others, but I find all the couple shrines interesting, be it normal, Yaoi or Yuri (although I have yet to find a yuri yu yu page ^^;;) Keep an open mind and you'll have more fun!

Yuusuke and Keiko of course, the most obvious couple there ever was.
Kurama and Botan quite and extensive page too...
Ko-Enma and Botan Gracious there are a lot of these ^///^
more Ko-Enma and Botan
Hiei and Kurama