Homebrew definitely tops the list of must-haves - it makes managing various tools and applications a breeze, and even has built-in capabilities for easy snapshotting. I like this tool because it has similar keyboard shortcuts to Windows, which makes muscle memory work to your advantage. The folks making the tool have put a lot of thought into making it adaptable as well - it takes your location and time of year in consideration to make sure that automatic adjustments are done properly.