Note: This question is specifically about installed, desktop software. There is another question specifically about free cloud-based software and services.
What free programs should every GIS user have installed?
I'm not necessarily referring to ESRI extensions or open-source products, but others that increase your productivity and ability to handle GIS tasks.
I posted this question awhile back now, but have found that I am using Google Tasks daily and I think it's worth mentioning. It's not GIS-specific, but it's a great tool, especially if you independently and on multiple projects where purchasing time-management software isn't reasonable.