My workshop... Or my lab... Or, in other words, my room. I wish I did have a separate, dedicated, workshop! Or even a garage would do as a makeshift nerd cave (since I don't have a car to keep in there). In addition to doing electronic stuff, for which I have a bunch of test equipment, I also occasionally need to modify, frobnicate or create some mechanical doohickey, be it an odd sized bolt, an odd shaped nut, a clamp, holder or adapter, or a launch lug for an amateur rocket. On occasion I also need to make (or modify) circuit boards for various electronic things. So I have filled my room with a variety of stuff.
What's still missing? I wish I had room for a lathe, and a bigger drill press that could take bits up to 10 mm or so. If some day I finally apply for and receive a permit to put antennas on the roof of our building, I'll have to squeeze in my amateur radio station as well.