VMware ESX
As has been previous documented, we have a *lot* of VMs for Release Engineering purposes. We often need to start, stop, edit, or do other management things to them. For a long time this meant using the Virtual Infrastructure client, which is...quite buggy, and only runs on Windows. Awhile ago I discovered the VMware Web Interface, which let me start and stop VMs. Just now, I realized that I can actually edit settings, too. This means that I no longer have to start up a Windows VM to do 99% of the things I need to. VMware, you're web interface kicks ass. Now give me an MKS plugin for Firefox on Mac and I'm all set!