Expecting a software release to be free when it includes major interface changes and functionality enhancements is a bit asinine. Microsoft is obligated to provide you with patches that fix bugs from the initial software release. That is all.

I assume you were aware of the feature list when you purchased the Vista license or the pre-built computer on which it was installed. What makes you think updates should be free if they include new features and enhancements that didn't ship with your version of the product? If you buy a 2008 Civic that doesn't have navigation as an available option, and Honda releases a 2009 model with navigation, do you drive your 2008 back to the dealership and demand they install a navigation system at no cost to you?

MS patched Vista and it's now very stable from what I've read. They completed their end of the bargain.