Here are some dot maps to peruse:
Chicago Race/Ethnicity and Income: http://www.radicalcartography.net/index.html?chicagodots
A series of maps inspired from the previous set for 103 differernt urban zones in the US: http://www.flickr.com/photos/walkingsf/sets/72157624812674967/with/4982043082/
A bit more for Graduated Symbols:
neat graduated circle map I just found projecting US pop in 2050 with graduated circles emphasizing major urban centers: http://www.rpa.org/america2050/images/2050_Map_Megaregions_Influence_150.png
Interactive tool for generating a legend for a graduated circle map: http://jenny.cartography.ch/legend/
And just some interesting maps:
Arctic map showing change due to ice melt: http://urbanomnibus.net/main/wp-content/uploads/2009/03/arcticmap.jpg
Change (and projection) in US pop 1970-2030 as a prism map (2.5D choropleth): http://3.bp.blogspot.com/_RBw-psMN_Ew/S-2DPSCCzoI/AAAAAAAAHjI/TeRzMDtrFrA/s16...
