We have been a part of deployment projects with Windows XP and Windows 2000 on very large scales in the past, and now are getting our hands dirty with Windows 7. This deployment is for a SMB only of about 40 computers, and so far, we are very impressed.
Microsoft has come a long way with the deployment process of their operating system. At first, understanding the steps and deployment stages can be daunting, but a quick read of the unattended settings using the documentation provided with the System Image Manager makes things a breeze. The WIM format and ImageX tools allow us to overlay application data onto the drive in layers, instead of creating drive images and then copying loose files over-top.
The goal with any deployment project is to minimize deployment time on the day-of, and there is some time spent with the WIMs that I think could be faster, but it is fast enough for a complete corporate install in about 2 days with only 2 techs on about 40-60 computers. We found a way to do this without the purchase of any third party tools, also!
... Does anyone but me remember those weekends being stretched to the limit installing Windows XP by hand, and then installing all the applications afterward?
The time savings actually makes this deployment pay for itself in the long run, too. New computers introduced into the company can be completely generated in 30 minutes. No more ordering from your computer supplier and then stripping all the settings that you couldn't remove with Group Policy.
In conclusion of this brief article, anyone having to install an operating system (or returning an operating system to a base state) should be thinking automated and unattended deployment first - especially if 5 or more computers are involved - it is simple, cheap and very reliable.