Under Vista the 'power' button defaults to Sleep mode instead of actually shutting the system down, so you can be up and running in less than 30 seconds. When actually shutting down it takes a little over a minute after being tweaked. (All unnecessary services have been disabled.)
John
Get out your stopwatches. How long does it take for your computer to boot up?
* Less than a minute (What's your secret sauce?)
* 1 to 2 minutes (Not bad. Any tips?)
* 3 to 4 minutes
* 5 to 6 minutes
* I can mow my lawn and return, and it will still be loading.
* Other (Please specify.)

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic