Well not quite room temp, but ~55-60 degrees is best for many varieties. It really depends on the brew. Take Founders KBS for instance. Considered one of the best beers in the world by many, which I was lucky enough to come across on tap once, if served too cold would taste much like any other stout. Serving beer cold can make it refreshing, but it hides the flavors.... which can be a good thing as well, depending on the beer.