I am responsible for more than 100 PC's in a medium sized company, and when I install new PC's with the default windows settings, I always wonder which settings could actually be changed to optimize the PC for performance (without loss of functionality).
Our default PC image includes office apps and a lot of security apps, so the initial boot time on a brand new Lenovo T400 is more than 3 mins. Of course network domain and logon scripts is a time consuming factor, but still I feel there's room for improvement in the OS.
We still run WinXP, but most core settings in both WinXP and Vista have roots back to Win2000 and NT, so please share your answer regardless which Windows Version you use. (If your setting is Vista specific though, please indicate this in your answer - Thanks!).
So to my question:
"What default settings do you change immediately after installing windows to optimize for performance, while not losing functionality?"
(If you turn off things like firewall or built-in DHCP services please explain your reasoning behind it - why are these services unnecessary in your environment?)
Also, if you change many settings, please put in multiple answers with only 1 setting and explanation in each answer, so we can vote on them separately - Thanks!