It depends upon the keywords, who you're trying to market to and what you plan to do with the name. It's not as simple as listing a pecking order.
However, my personal preference given all other things being equal:
com
us
net
info
org
premium cctlds
eu
less than premium cctlds
biz
Again, this is based upon what I'm doing and my long-term business and development strategy. Your mileage will most certainly vary.