I love Blue Cheese Sauce, and have tried a few different ways of doing it. Usually I just got for sour cream and blue cheese and mix it up, this is nice but never quite creamy enough.
Today I went for
1/2 cup Sour Cream
1/2 cup Mayo
4oz Blue Cheese (I just use Asda's cheapest one)
a sprinkle of Cayenne
And it seems pretty nice!