Saki

I think Gin is obsessed with Sherry. I find it very interesting, actually- like they should be the pin up couple for Lady Gaga's 'Bad Romance' song- lol! But seriously. She hates him, but he seems to really* want to find her. Does he want to kill her or torture her or keep her? I hope all ends well for her and she doesn't get hurt either way.

I think both sides (ShinRan and ShinShi) have equally good arguments on compatibility but IMHO, I think a person should be with who he loves best regardless of who would be a better match for him. So, my vote goes to Ran here because Shinichi loves her* and she loves him in return.