It looks like Windows PE can be used more then just to install Windows NT 6+ (Vista/2008/7/2008R2) or as a recovery console. It can be used to run a head less server (for virtualization with MOA). If I understand the new EULA (i think) you can post how to modify WinPE, but you are not allowed to distribute modified version without extra license, in other word you don’t need to be a system admin for a big company, but still be able to use it for personal use.
With new optical diskless systems (like netbooks and nettops), there is a new use for WinPE (or at least for WinPE 2+). WinPE2+ can be used to install Windows NT 4+ (although there is no reason to install anything under Windows XP). WinPE can be used for all install, recover, create/restore image, etc. I think it is time to create some sort of tool to create a Windows XP USB Installer, and integrate some more advance recovery tools to WinRE (special WinPE build from Microsoft for recovery purpose).