Another +1 for dhammer53's basic advice: ask at a local wine store. The staff there are literally paid to be able to help solve questions such as yours.

I disagree with the advice of buying 12 different labels, though. Unless the purpose of your event is specifically to taste a wide variety of wines, you'll be better served by limiting your selection to 2-3 types. Going with a wider selection means more bottles opened simultaneously, more confusion about which one is right, and more waste. I recommend selecting a good, basic white (I like sauvignon blanc), 1-2 reds (lighter or heavier depending on the food), and 1 champagne if your plans involve an appertif, a toast, or a brunch.