A pretty nifty blog post entitled Why PHP Won lists 4 main points as to why the adoption of PHP for most Web projects today outpaces those built on Perl CGI.
You can read the post Why PHP Won here:
I also begin with Perl CGI/FastCGI on my first major project. I haven’t worked in that environment for over 2 years now and don’t see going back unless for some reason it’s something I walk into. The LAMP stack is cheap, fast, and pretty universally accepted for fast and nimble development projects.