Ritsu: My favorite
Great at setting off events leading to a fun plot.
Tsumugi: I'm still interested in her take on everyday life. Too bad there weren't more Mugicentric episodes...
Azusa: She's grown on me throughout the second season, and at the end I really want to see more of how she'll do as club president.
Jun: She stands out from many of the other minor characters in a good way. Another reason why I want to see what's going to happen to the club.
Himeko: 
Other: Shizuka, cause she's just adorable, and often smiling.
Closely followed by Chizuru (glasses + forehead)