The primary laptop that I use (Thinkpad) just got re-installed tonight. I was using the Beta / RC of Windows 7 Since Nov of 2008. I just realized that it was due to expire in the next 2 weeks. Early last year I purchased 3 copies of windows 7 Premium for 50 dollars each on Amazon during a pre-order event. I just had never taken the time to re-image / install.
The wonderful thing about this install was that there was no upgrade. You just get the joy of a fresh install.
I did use my new favorite installer (http://www.allmyapps.com) to get all my easy applications back.