Want to get all the SysInternals utilities? You can download them all yourself, or there's a really useful SysInternals installer built by Ross Smith II that downloads them all (or the ones you select) and creates shortcuts for them for you.
He also has a similar utility for the NirSoft utilities, which include excellent tools for recovering lost passwords and product keys. Watch out if you run Symantec AntiVirus, as it will suggest they are "hack tools".
Another useful meta-utility is The Ultimate Boot CD for Windows. Built on BartPE, the free and legal Windows LiveCD builder (you must have a license for Windows to use it, and you must not use it on more than one PC at once), The Ultimate Boot CD builds you a bootable image with dozens of useful recovery utilities on it. Every sysadmin should have one.