postmortem debugging tools, for Windows that is:
- umdh (for memory leaks)
- drwtsn32 (for crashes),
- cdb (to get minidumps from hung apps),
- windbg (to inspect the minidumps).
Also put a symbol server on there to store your own app's symbols (without having to remember which set correspond to which version of the app)
These are all things to help debug apps as if they were run on a customer machine - not your development machine with its debugger, sources, symbols etc. If you can diagnose problems there, you can take the tools onsite to fix problems you'll never see when you run them at home.
Also put a file share on and store all the installers for development tools you'd use - so you can easily get all the bits you need to set up a new development workstation.