Microsoft is doing a pretty good pre-order promotion for Windows 7 that offers upgrade versions of the new operating system at a greater than 50% discount. Amazon is making the deal even sweeter by offering free release day delivery of Windows 7.
Unless you bought a notebook since June 26th with Windows Vista, this will be the cheapest upgrade path. Based on my experience with Windows 7, I think its a significant improvement over Vista and at $49.99 (for Home Premium) a must have.
This end July 11th or when supplies end, so get on it soon!
http://www.amazon.com/dp/B002DHLUWK