Although I am reinstalling machines on such a regular basis, I keep forgetting enabling tab completion for cmd.exe. Therefore I am putting a note to self in my blog...
Where to define:
How to do it automatically (copy / paste / save as .reg / double-click):
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Command Processor]"CompletionChar"=dword:00000009