I really never gave a shit or two about what OS my developer had on his laptop. Since he probably had what worked for him in his personal space.

I had development groups with project managers they called the shots with the producers and stakeholders on what tools were to be used in the project. If we were working on a webservice that interfaced with a product that was on a Windows server... Then most likely windows knowledge was a +.

In my opinion, most good developers know their way around several OSs and languages. They are just tools so they have an understanding of the tools they need for the job.

I personally don't know that many programmers that work in OS X. Linux on the desktop/lap is fairly new, so if a guy has a windows box at home. It wouldn't bother me one bit.

This cat is full of himself and his puny company. There's a 100 guys on here with better advice.