SysInternals tools have been awesome since day 1. I always like to keep them handy, but you definitely don't want them lying about where "regular" end-users can reach too easily.
These days, I keep them installed and up to date on my own systems via Windows System Control Center. It's a free utility that bundles SysInternals tools and NirSoft utilities, and makes it easy to check for updates and new utilities. It also includes shortcuts to many built-in Windows tools, some of which can otherwise be hard to reach.
Come to think of it, I'd love to see some of the NirSoft utilities get the same "How-To Geek School" treatment sometime. There's a lot of great stuff in there.
One additional word of caution with WSCC and the NirSoft tools: Many of the utilities in that bundle are password recovery tools or other things that one might call "hacking tools". As such, some malware scanners may alert and quarantine those files.