First up is DIA at http://www.makeuseof.com/tag/a-free-open-source-alternative-to-microsoft-visio/
More at http://www.osalt.com/visio
I'm looking for software (preferably free) to use for simple drawings. I use an old version of Visio on my old PC, and recently bought a new PC. I don't want to spend a bunch of money on something to design next year's garden layout!