Here's a few reasons I'm using ASP.net using C# instead of PHP for my zip!Contacts project:

• I work in PHP everyday, and it's much easier to come home and not have to do the same thing I did all day.
• I fell in love with coding when I learned C++ back in 2003.  ASP.net reminds of that.

Now, some will tell me that PHP is faster performance-wise, etc, etc.  Well, I can worry about system speed and more later on.  Right now, the primary reason I've chosen ASP.net is that I enjoy it.  Plain and simple.

If I can't get myself excited about the working on the project, it will fail, and this time, that's not going to happen.