Hm.. Well, water is my favorite type, but since fluvr305 pretty summed up my feelings on that one, I'll go with my second favorite: Fire. There are a few Pokemon that are an embarrassment to the already lacking type, but for me the biggest offender is probably Camperupt. Such poor stat distribution for what could be a great sweeping type combo.
I was really hoping that Fennekin's evos would correct this, but with the leak being basically confirmed at this point, that doesn't seem to be happening. Maybe they can give Numel a split evo based on an Alpaca or something...? They are like twice as fast as camels near as I can figure, though I'd just prefer a new Fire/Ground Pokemon that is built for sweeping.
1: If you think your opinion is fact, then I will ignore you. 2: If you butcher the English language or abuse Netspeak, see #1.