QUOTE(Darin McGrew @ Nov 1 2007, 08:42 PM)

I've never worked anywhere that used PHP.
Me neither.

I also forgot to mention ASP, which might come second after PHP. Not sure if it's possible to get any reliable stats, but according to Google the following figures apply to the
text content of web pages (i.e. supposedly excluding URLs):
341,000,000 for "php"
224,000,000 for "asp"
103,000,000 for "perl"
103,000,000 for "python"
19,900,000 for "ssi"
My guess is that most pages containing these words are tutorials, code examples, forum discussions etc. Such figures may or may not say something about what "ordinary" sites use.
Looking at URLs only, Google turned up:
1,370,000,000 for ".php"
573,000,000 for ".asp"
291,000,000 for ".cgi"
191,000,000 for ".shtml"
168,000,000 for ".jsp"
52,300,000 for ".pl" (which is also the TLD of Poland).
Of course URLs will not always indicate which server-side language (if any) that was used.