At work I don't have a fixed Windows environment. So every time I need one I get a newly imaged machine and need to reconfigure it. These are the steps I always go through to configure my Windows XP environment to prepare it for development work.
Create an OldIcons folder on the desktop and dump all icons into it (excluding MyComputer and the Trash). Icons such as IE which can't get moved get deleted.
Unlock the taskbar, add the quicklaunch toolbar.
Download a zip with essential utilities and unzip it to c:\mine. Make a link from c:\mine to the Desktop. The zip includes a subset of a larger set of free Windows software I normally keep with me.
Open the start menu, right-click and configure it.
Check show clock
Uncheck hide inactive icons
Customize start menu
display admin tools
display control panel and my computer as menus
hide everything else
Customize a command prompt icon and put it in the quick launcher.
Increase buffer size to 999
Turn on quick edit and insert modes
Lucida Console font, yellow screen text
Change the default view to List, edit the folder options from the Tools menu - view everything, hide nothing.
Run and configure Process Explorer (already included in the zip). Include username, handles, threads, working set size, remove company, description, lower pane.