I wonder why it took me so long to make a comment about the characters...
I think Kannagi had one of the most entertaining and enjoyable cast of the past year. Each one of them--with his/her strange quirks and different antics--made the show for me and I would pick all of them as favourite...
(if I ever feel like voting in a poll again)
On the other hand, I would have no issues to choose the three heroines (Nagi, Tsugumi and Zange; yeah, even Zange) as the most likeable and funny characters of recent memory. With their dynamics and interactions with the rest of the cast, it made of the show a guilty pleasure to watch every week; and even now, I would still miss the great feeling and excitement I got.
Really, nothing can replace Kannagi and its cast of wonderful characters...
honourable mentions to Takako-sama and Akiba-kun for obvious reasons (fuyoshi X otaku... XD)