By far the best starting point for any engineer is the PortableApps USB Stick. This really is the powerhouse of tools. What makes it unique is you can install a massive amount of standalone applications on your USB stick, and run them with no additional installation required on the client PC. This is useful for those systems that are reasonably secure, but still allow you USB access. Check out the suite here:
Link: http://portableapps.com/
Download: http://portableapps.com/download