According to CAMRA (Campaign for Real Ale), the recognized authority for cask-conditioned, hand pulled bitter, the optimal temperature for real ale is 54-57 F, somewhat cooler than room temperature. Anything warmer will do just as much to ruin the experience of the ale, as the natural carbonation will suffer as well as the taste. A colder temperature will often mask the intended taste of the ale, which can be just as ruinsome as improper carbonation.

Lagers, of course, should be served cold, as this is how they are intended to be served when brewed.

Artificially carbonated ales can be served somewhat colder than real ales, but not too much, or you'll mask the flavor.

yes, my name is Mike, and I'm a beer nut.