Gilde Ratskeller is the beer of Hannover so when I visited Hannover it was mandatory for me to try it. It is a classic style pilsner. Very drinkable and head and shoulders above many other pilsners. It is apart of the ABInBev drinks stable.
If you visit Hannover the best place to stop for a Gilde Ratskeller, is the Gilde bar in the covered market. Cheer, Proust, Bottoms Up!