The 2007 winner was a lager (Brooklyn Lager), and the 2008 winner was an ale, Backdraft Brown (although they classified it as a "dark beer") -- two very different beers.
Already Raven Lager has a strong showing as well as Brooklyn Brown Ale. I would love to see Ommegang Hennepin (Ale) win, but specialty beers don't win overall contests -- session beers do. That's why I'm afraid that Budweiser's American Ale has also made it to the semifinals. I've tried the American Ale -- and it's OK, nothing special.
Also in contention is Troegs Hopback Ale, Barney Flats Oatmeal Stout (Ale), Left Hand Juju Ginger (Ale), and Tommyknocker Ornery Amber (Lager).
So the match up is 3-1 ales against lagers. Lagers are good for thirst quenching, ales are good for flavorful drinking. A lot depends upon the judges' palettes. Me, I'm an Ale Guy. I went to the interactive brackets shown above and it seems that my tastes are in line with the majority of the respondents (which has no bearing on the actual contest).
So far I picked the "winner" every time. Ha! Victory in the it-doesn't matter category!