When the first state quarters came out back in 1999, I decided to collect them all, since I figured it would be a simple matter of picking out the ones I needed from some loose change. My parents got me a collection book to put them all in, and as the years went by, I slowly filled in the map. By the time the last of the state quarters were released, I was missing only one: Arizona. It wasn't until literally just weeks ago that I finally found that one state quarter I had been missing for years.
It seems collectible quarters didn't stop with the state quarters in 2008. Those from 2009 seem to be of U.S. territories, and of these, I have District of Columbia, U.S. Virgin Islands, and American Samoa (I assume the only ones I'm missing are Puerto Rico and Guam). All quarters since then are for National Parks, of which I currently have seven, though I can't immediately remember which ones they are.