For work? Ignoring corporate computer supply, the short list is MS Office, PVsyst, ArcGIS, WindFarmer, Windographer. Most niche industry software is based on windows.<p>I can do a lot with QGIS (which I love), but there's no real replacements for the other tools that are cross platform. You can do a lot with SAM or pvlib, but you can't produce a bankable energy assessment using them. WINE may be a possibility, but at that point we're just on Windows.<p>For not work? I use a Mac most of the time, and have a laptop that runs Linux which I use for some specific tasks.
Esoteric and low level stuff is keeping me away. Having had bad experiences with drivers, disks and the alike.<p>Time. Convenience.<p>But it's actually a really good question.