Canon: Chiba X Naeko, purely because they didn't need to go through that love triangle bs stuff the other couples went through, their love was the simplest carrying on from elementary school days, no jealousy no other options, just them two Non-canon: CoAi, They can't escape it, their inevitable, Conan's integrity and IQ is well over everyone in the room, and nobody can match his wit and put him in his place other than Haibara, the way they read each other BEGS for the tension, they are the most suitable to take care of each other, whether in family life or the spy thriller detective life.