Started to use Windows Vista Ultimate and Office 2007. I am using legal copies so hush.
Hardware is a laptop I recently bought through an auction site. It is a worthy platform but not ideal. I had to add 1GB to run Windows Vista.
The operating system installed without incident and much quicker than I anticipated. To date the only driver issue I have is with the integrated sound card. Contacting Compaq/HP was simply replied with "Windows Vista has not been officially released so driver availability is not advertised at this time". Odd since Vista Business was released earlier this month and the full release(s) of Windows Vista have been made available to MSDN subscribers.
I did buy a trackball to use because the glidepad (I am not a big fan of them anyway) operation was unbearable. Windows Update has provided a better driver that allows you to configure the sensitivity in great detail.
All in all Vista has some interesting features and enhancements and in general performance is equal to if not better than WindowsXP.
Office 2007 introduces a big learning curve.