.net and .org maybe to back up your .com, id even agree with .co.uk if targeting traffic to the UK etc, however i disagree with the buy all the extensions to defend your domain, I never would buy a .info domain nor go onto a .info site With one exception, type "pagerank" into google, and number 1 result is a .info domain Bizzare
an increase in tlds does nothing more than fill the pockets of those who create it. I also think in a way it effects the prices of the extensions we hold dear .com .net .org. I mean you can't sell real estate on the moon without having some effect on the real estate market of the earth.
And who is going to get Coke.xxx or IBM.xxx hehehhehehee I like the idea, but enforcement would be impossible.