But not as much as people think and no developer or designer host ur website on your own pc . they go for hosting companies and Hosting plans of linux and windows has not much difference. and c# is a superior language than PHP.
c# developer can make Web Applications, Windows Desktop applications, Windows Mobile Applications, PC Games, XBOX 360 Games, Games for Zune and many more .
and for Database MICROSOFT provides absolutely free : http://www.microsoft.com/express/sql/default.aspx
c# is just the same as java though