I liked Windows 7 so much on my desktop machine that I took a chance and upgraded my Sony VGN-SZ2XP laptop as well - to Windows 7 Home Premium - knowing that Sony were not making Windows 7 drivers available for their old XP machines.
As long as I keep the Stamina/Speed switch on Stamina, I get a good display, and the machine is way faster than in its XP incarnation.
But one major niggle is that Windows Mobility Center does not have a "Display Brightness" panel. Its help says "If a setting doesn't appear, it might be because the required hardware, such as a wireless network adapter, or driver is missing or turned off."
So I am now looking for any way to control the screen brightness, in Windows 7, on a VGN SZ-series laptop, please...
(I figure that once I have found a way to control the brightness, I can tie it to Fn keys using the excellent AutoHotKey.)