Tara Millgrove
thinks
the sudden push by the domain registries for .co is a cynical attempt to get people to buy their domain yet again. .com, .biz, .info, .dot …
Tara Millgrove
says
besides, .co is the country code for Columbia, and does not mean "company".
Valiant
says
.com still rules, although with the evolution of search, high-level domain value is increasingly diminished.
.dot? Seriously? 
Tara Millgrove
says
I just made up the .dot; but don't tell Network Solutions, or they might run with it. 