A recent post on the GIS and Science blog noted that submissions are being accepted for the 26th volume of the ESRI Map Book. If you have a map made with ESRI products then you can submit your map for consideration by the end of Geography Awareness Week, Friday, November 19 at 5:00PM PST.
If you have attended the ESRI International User Conference then you probably have a copy of one of the Map Books gracing your shelf, and it is (in my opinion) the best part of the SWAG bag that you get with your registration. If you have not had a chance to check out one of the hard copies, however, you can access volumes 1 and 20-25 online. The online version provides descriptions of maps along with full views of the maps along with PDF versions of the pages from the map book. I have been using the Map Books as examples in my Intro to Cartography class to show the wide range of design approaches.