I think each language has their strengths. Here are my feelings towards PHP, ASP.NET, Perl, ColdFusion:

PHP - Most growth potential out of all. Rapidly gaining more and more followers. The best choice for small to medium sized businesses due to its price and wealth of free resources. Highly compatible with many OSs.

ASP.NET - Currently a hot technology and medium to big business are questioning its potential. Because it's Microsoft branded, it's here to stay. Also, it's probably the highest in demand when it comes to web development jobs.

Perl - Good language to do administrative tasks on Unix/Linux operating systems. Low development cost compared to other languages. Highly compatible with many OSs. Contains good parsing and a huge amount of resources, like CPAN.org.

ColdFusion - Easiest and fastest way to do web applications. A lot of functionality comes right out of the box, rather than installing modules or components. Great error trapping/reporting. Can integrate with anything written in Java and therefore has most of Java's advantages because all CF pages get compiled by a Java engine and handled as Java Byte code.