Microsoft has a gift they want to give you: free Windows deployment tools and guidance. The best part: the guidance isn't just for Windows clients, but Windows servers, as well. The gift's name is Microsoft Deployment Toolkit 2008, or MDT for short, and it's the successor to BDD 2007, the Business Desktop Deployment Solution Accelerator.
If you are currently using BDD 2007, I strongly recommend that you look into Microsoft Deployment Toolkit 2008. You will find many goodies in this update, and the transition isn't terribly complicated. Microsoft Deployment Toolkit 2008 offers upgrade paths from existing BDD 2007 setups so you can take easily advantage of the new features.