This is of some interest. The Washington Post lists the 50 top web domains as of the end of February, 2006. Heading the list is Yahoo.com, followed by Google.com, msn.com, aol.com, ebay.com, microsoft.com, passport.com, mapquest.com, hotmail.com, and myspace.com. Check the link for all 50 domains. There might be some surprises. I found some I had not heard of before. The accompanying Washington Post article can be found here.