I run several Vista machines each with several user accounts. Sometimes the different accounts are for different people, sometimes they are for different purposes with different permissions (ie development vs testing). Windows XP introduced a featured called "Fast User Switching" that allowed you to log into another user account without logging off the current session and Vista improves on this by allowing it in domain environments too.
But it's not enough. I want it to be faster. At the moment, in Vista, it takes far too many key presses or mouse clicks to switch to another user. This is the quickest method I've discovered so far:
Ctrl+Alt+Del, Alt+W, select account, enter password, Enter.
However, I recently discovered a much faster approach. I bought a new laptop with Vista and a built-in Vista-driver-compatible fingerprint reader. Now I've associated different fingers with different accounts and at any time I can just slide the appropriate finger over the reader and *bam*, I'm logged into another account.
Still, if anyone knows, a better keyboard shortcut would be great for the PCs without fingerprint readers.