Right now, it seems to be a matter if faith regarding which TLD of those 3 you want to invest in. People recommend all 3, to cover all the bases.
I have seen some nice development on .info sites. It is truly a world-wide name, understood in many/any language.
Less enthusiasm seems to surround .biz. Was this an alternative for .com, to open up another 93 million names?
Long term, .us will be in highest demand among the 3.
People that live in the US, people that want to develop a business presence in the US, these will contribute to the demand for .us names.
There are strong national markets for .kr, .jp, .com.uk, .de, .au, and others that have been available for years. Lets see what the 1 year mark brings for .us.