Fixed in Windows 8 is intra-line tab completion - you can try it out on the Windows 8 Consumer Preview now. If you open a command prompt, type a command, then move your cursor back into a token in the middle of the command and tab complete, the tab completion works on that whitespace delimited token and doesn't erase all text following the cursor. Like it does in pre Windows 8. And annoys the hell out of me. Yay!