Found this article today, and it's pretty interesting. How TurboTax has been lobbying hard to keep from the automated type of tax filing many other countries see.
Personally, I'd love to see something like England where you get basically a tax code, everything comes directly out of the check. If you get overcharged, you can get it back, if you get undercharged, the gov't sucks it up.
How the maker of TurboTax fought free, simple tax filing | Ars Technica