I think this is very subjective to where in the world you are. In the UK, especially in larger businesses, PHP is rare and C# / ASP.NET / .NET are fairly very common. Rates for PHP are also generally lower.
As an example Jobserve.com, one of the major search engines for jobs here, has 501 PHP jobs, 1,100 ASP.NET jobs, 2,736 .NET jobs and 1,954 C# jobs (search against UK, Europe and Middle East but most of those will be UK).