Unless I'm dressed up for a performance or work (I'm studying to be a Music Teacher) I literally wear nothing but blue jeans.
They are so darn comfortable, are widely accepted pretty much anywhere you go, and they are made of a nice, sturdy material that doesn't stain too easily and is perfect for hard work outside.
In fact, I wear blue jeans so often, that it earned me the nickname "Denim 4 Lyfe" at the summer camp I work at. I have since changed my YouTube screen name to denim4lyfe.