Why do you use PHP rather than another language? Was it the free access to code pieces? Was it what they happened to use already at your job?
BellaOnline uses both ASP for the main website as well as PHP for these forums, so we are multi-lingual
PHP makes for a good fourth or fifth language, but I really wince when someone uses it as their first. Since it allows a programmer to define their own structure, it is extremely flexible, and gets out of your way immediately. The lauded documentation is also a big plus, and together with native web service handling is probably why it still has such a usage share over Python.
I suppose I should just say, I like PHP because it's the web's version of Rapid Application Development : )
These forums are the only reason I still use PHP. Then again, I still use ASP coding on my other sites, so that's fairly ancient, too :). I'm really not up for the task of recoding those, though. Anything I could, I've already converted over into WordPress.