Interesting article on law.com:  A Look Back at the Year in Tax Law, by Sean P. Kanousis:

The year of 2006 played out like an off-Broadway drama. We had new tax schemes enacted (Texas), other long-standing ones repealed (Michigan’s Single Business Tax and Florida’s Intangibles Tax), exciting constitutional dramas (the California LLC Fee; West Virginia and New Jersey’s assertion of their corporate tax on taxpayers without a physical presence in their respective states) and a climax with the defeat of H.R. 1956, which was federal legislation that would have required businesses to have a physical presence in a state before that state could impose their corporate taxes on the business.