I received my copy of Windows 7 today and have it installed on an old HP Pavilion ZE4900 laptop. Install was painless, found all devices but sound and modem. Display is less than what is needed so Aero does not work but the machine is very fast. I had Ubuntu desktop loaded and it is as fast as that was. I have an overall score of One, so the hardware definitely leaves a lot to be desired. But XP barely ran on this thing anymore and Vista was out of the question. Chose Win7 Business x32.
I have a newer laptop running Vista x64 that I will upgrade soon. Until I have time to get to it I will keep testing this old thing. So far so good, much faster.
I will keep you posted on the progress.