I recently purchased an Acer 5610Z laptop with Windows Vista Home Premium pre-installed. It has a 1.6GHZ processor, 120 GB Hard drive, and 1 GB of RAM. I played with aero and wasn't impressed. I did notice that programs seemed to run a little faster than on XP though. After a month of using Vista and running into incompatibility issues with many of my programs, I decided to go back to XP.
After I installed XP Pro on it, the sound and wifi stopped working. Thanks to the Acer website, I got the drivers and everything works great. Now, all my programs work and I don't have to buy newer ones. I recommend that everyone stay with XP until Microsoft fixes Vista. It may take a year or two, but until then, XP is the operating system of choice.