I always thought Hibiki and Midori were the best pairing seen in all the toku shows I've seen so far even though the romance part was just hinted at.
But we're getting off-topic. I can't believe nobody's mentioned Kagami and Bocchama Tsurugi.
Since you seem to be talking real, straight pairings, Hibiki actually involved real relationships, not just subtext.<<;
Two words: Bathtub scene.
Two words: Bathtub scene.