This post on the JankoAtWarpSpeed blog started off a discussion between PHP and ASP.NET developers as to why one would go for the first over the second.
The first thing that came up to my mind was that PHP is quite simple language comparing to ASP.NET (.NET actually) which is a complete framework that offers a wide range of possibilities (yeah I made a comparison). Maybe PHP has a simple learning curve comparing to ASP.NET, but why would web designers care for data access layer or OOP anyway? But on the other hand, it doesn't mean that web designers should limit their selves just to PHP. Why not be familiar with other technologies as well?
The post has lots of comments from both sides of the fence, each espousing their language of choice. Reasoning ranges from "because ASP.NET is a Microsoft product" to the price of ASP.NET hosters to PHP's open source-ness and the much different learning curves.