I have been in IT for 15 years and this debate has always been on my mind. My current philosophy is LAMP are the backbone of the internet as well as the web developer’s platform of choice. They are stable and with good admin, hardening and securing, just let them go.
But I have to say Microsoft server 2003/2008 Exchange 2003/2007 and Sharepoint 2003/2007 are great stable products, keeping them the backbone of the business network loaded with productivity features.
Macs have found their way in as well and are my workstations of choice after years of going back and forth.
There was a time in my youth where I could have been considered a Mac evangelist that I was willing to fight anyone on the point of why would you use windows. For this old IT guy I finally enjoy the debate as each has found a place in my working technical life.
Now when will someone put out a great international multilingual server based accounting software and once that is solved let’s move on to pay roll.