Quiet tires are usually softer rubber and wear out quicker - tread patterns that are fine with the blocks closer together. The more rugged types that might have more off-road potential and have bigger tread blocks and possibly be a bit harder will be less quiet.
I bought my 2010 Q5 from a neighbor. It had 30,000 miles on it and the original Dunlops were worn completely down. I did some research and liked what I read about the Bridgestone Ecopia tires. I got a great price and then on New Year's day there was a coupon for another $100 off the set of 4, so I went with them. I've done about 4,000 miles with them so far (mixed highway and around town) and could not be happier with the grip, ride, wet/dry handling and fuel economy. I highly recommend them (Virginia, USA).