Windows has been a good product for the average user since 1995, and has been great since Windows 7; it's just their business practices that were a problem. And to be honest, they were hardly the worst offender there either.

An interesting, speculative discussion would be to examine if the harm (if any) that came from Microsoft's monopolistic activities is out-valued by the good done by Gates in his foundation.

Where would the value captured by Microsoft and Gates have been redirected if MS didn't have a monopoly on the PC industry until recently? My guess is not fighting tropical diseases- but where?