I ship Kiyoshi with Hana, so sure I'm choosing Hana (and I'm glad I see there's someone who think the same).
It seems for me that deep inside Hana is enyoing all much of the stuff with him, but she don't want to accept it...
Well, Kiyoshi with Chiyo would be a nice couple as well, but she's too normal for me (I don't like girls like that too much in mangas)