I prefer to use a brown ale-ish type beer. For the fondue you ate, I used Sam Adam's Summer Ale.
3/4 c beer
1 lb shredded sharp cheddar tossed with 3 tbsp flour and:
*1ish tsp double ground mustard
*1 tbsp worcestershire sauce
hot sauce to taste
Rub fondue pot w/fresh clove of garlic
Pour in beer, set pot to 375*
When boiling, slowly stir in cheese mixture. Stir, stir, stir...add hot sauce...turn to warm, keep stirring until smooth.