At home I run GNU/Linux (Linux Mint), and all the software there (apart from Minecraft) is Free/OSS. I do have a copy of Windows to boot into so my wife can play Plants vs Zombies (I had it running under wine, but it didn't always work perfectly), and occasionally Half Life or Portal. I also have a lot of console games that aren't F/OSS. Really it's just the games that aren't, but I'm really not bothered by that.
At work (I'm a post doc research assistant, modelling E.coli O157 spread in cattle), in one office I run under Linux, and the only non-F/OSS program I run is Maple, because there's no good alternative that I'm aware of. At my other office I use a Mac, and also Word and Powerpoint. I have protested at length about this, and my boss will occasionally allow me to use LaTeX (which she used in the past), but in general it's the collaboration part where things fall down. Also no journal that I'm aware of (and am interested in submitting to) accepts ODF documents, and Libreoffice (while I find far better for actually working in than MS Office) almost never seems to manage converting documents to DOC without things going wrong, especially the references.
My PhD thesis was entirely written in LaTeX, and the work done in C++, GNU Octave, Inkscape, and Maple (the odd one out). For presentations I used a mix of OpenOffice/Libreoffice and LaTeX. Ultimately, if I could be 100% F/OSS at work (and home except for games) then I would, but I'm not the one who makes those decisions.