at dealtime.com - I did a compare of the 60c and 60cs.
for the 60c included software/maps = City Navigation Maps, North America Maps.
for the 60cs = Marine Cartography, City Navigation Maps, North America Maps, Europe Maps, Australia Maps, USA TOPO, South Africa Maps, South America Maps, Middle East Maps, Asia Maps
everything else was pretty similar except they list the 60cs as having a fishing calculator as well.