CLOUDS!
Oh yeah. I love clouds. These are much more atmospheric then the usual photographs which is their strength -- this way they can be used in different orientations and in smaller bits without loosing much of the readability. I picked up #1, #7 & #9. These are three very different blues. I went for all three because there is not one color for sky with different kinds of day, light and year. It's also easier to match to other colors of papers, etc.