I assume that by now everyone is using PowerShell as their default shell, if not, time to get rid of that ancient cmd.exe thingy;-) If you are working within PowerShell, one of the powerful features is tab expansion. When you start a command you can type the first letters of the command, press tab and voila. But it does not have to stop there! Tab expansion can be extended, and that is whart a lot of people are doing!
For some background on tab expansion see the blog entry by the powershell team on this topic: http://blogs.msdn.com/powershell/archive/2006/04/26/584551.aspx
You can find a great series on developing tab expansion at monadblog.blogspot.com.
And /\/\o\/\/ has another great series at www.thepowershellguy.com
I'm currently using a tab expansion script from http://powershell.wiki.com/TabExpansion, it's wonderful!