my keg fridge has no temp control butusually comes in around 4-5 degrees - a little colder than I like it but I can always let the beer warm a little after it's poured
ferment fridge is set to 18 degrees for fermenting most ales
Depends what you're serving. A little colder for those crisp lagers, a little warmer for English beers. Somewhere between 2 and 8 degrees depending on the style and your taste.