A somewhat
complete listing of the factions.
Anyway, myself, I'm of course a
flagger. Everybody who can't see that
Harima and Eri truly belong together needs some glasses. ;)
Well, jokes aside. This pairing is the most different one and has enough potential to make the show. Adding Yakumo as competition leads of course to a few more funny situations. Tenma on the other hand is a lost case, she just fails to have any potential after episode one and a pairing with Harima wouldn't make as much fun as a HarimaxAnybody pairing.
Other interesting pairings:
Chinese Food Faction - Asou and Sara are a nice pair and good single characters as well, as seen in sukuran polls. :)
Flute Faction - Hands down, the childhood friends belong together.
Apple Juice Faction - Imadori may be a jerk but still fun and Karen deserves more attention!
True Oudou Faction - Just for the sake of it, they fit each other perfectly and should get together and disappear from the show so that we finally get more attention to the better pairings and characters. ;)
Cookies/Dynamite Faction - The teachers need love as well, Tae was pretty mean to him though.
Hmm, that's it from the top of my head.