According to me Technical environments depends on compay to company and also on the compatability of project like most of the projects supports Windows and 3 - tire application in case of Database
or some s/w will work on Unix / Linux so answer for this will different for different users
I have worked with Windows with SQLServer & Linux VM, AIX partition with DB2, now working with WindowsXp with DB2, with Tomcat 5.5 on java 1.6