Question : Upgrade Network to Windows 7

We have Windows XP Professional on our network.  What is the easiest and smoothest way to upgrade our network to the new OS?

I have recieved 50 User Volume Licenses.

Answer : Upgrade Network to Windows 7

Setup one machine per configuration (if you have 15 developers who need programming tools, 30 staff that need the same basic config, and 5 misc. machines, then I would setup three different machines, up to the point of joining the domain (install all software) and then image them to a Windows Deployment Services server.  Then read up on the User STate Migration Tool (to migrate profiles) and then use them both to deploy.  If you don't care about user profiles, then it's easier as you can just deploy the images.  

Check out the Microsoft tools for deployment, including:
MAP - Microsoft Assessment and Planning Toolkit - http://technet.microsoft.com/en-us/library/bb977556.aspx
MDT - Microsoft Deployment Toolkit - http://technet.microsoft.com/en-us/solutionaccelerators/dd407791.aspx
WAIK - Windows Automated Installation Kit - http://technet.microsoft.com/en-us/library/cc748933(WS.10).aspx
USMT - User State Migration Tool - http://technet.microsoft.com/en-us/library/dd560801(WS.10).aspx
WDS - Windows Deployment Services/Server - http://technet.microsoft.com/en-us/library/cc771670(WS.10).aspx

You can also check out my guide on installing WDS:
http://www.lwcomputing.com/tips/static/installwds2008.asp