I love CDNN!
I agree that the flat rate shipping is hit or miss, depending entirely on your order, but they always have great prices, usually the best I can find, on magazines, they have a great selection as well, and to top it off they quite frequently throw in little gift items! They have sent me a mossberg LED flashlight and a 'Magnum" liner-lock knife most recently. they have in the past sent me shooting glasses and other stuff, makes me feel good to get presents.
And they ship fast.