High Noon: Divide USA?

David Townsend (via Facebook): There are days when I think the country has gotten too big for its own good. Maybe the time has come to let Texas and the Southwest go their own way. The East Coast could be another country, as could the rest of the southern states. The Midwest makes another good grouping as do the Dakota, Montana and Wyoming.

Question: Can you think of any other easy division, should the states decide to go their own way?