I suggest to everyone who works inside my office to have a password protected screen saver and I completely agree with Mittens onion theory. The more security the better. And it's right on to say that if somebody is walking around and the person sees that your computer is just sitting there with Outlook (or whatever mail client) open that it is very tempting to look at.

I also suggest that people lock their computers as soon as they go away from their desks.

The one thing that I do tend to enforce is that our vpn users have more complex passwords.
I am more worried about security of the people who are on the internet with broadband (even if they have a router/firewall) than I am about our internal networks being attacked from the outside.