Windows XP Pro and IIS5 - Multiple Sites
One thing I hate about this, is that it includes IIS5 and you can't install IIS6 on it (not that I know of).
Why is this bad? Because you can only have one site... Which is something I got way to much used to running Windows 2003.
Luckily enough, Davy Belmans thought the same, so he developed IIS Admin.
It's a very nice tool, very small, and sits in the tray bar, allowing you to easily add new sites, and switch between them.
Yes, switch, because even with multiple sites configured, you can only run 1 at the same time apparently.
If you run Windows XP, and you don't have a way to get multiple sites working, get this tool, otherwise, comment and tell me how ;)