Bet the farm. Python or PHP?
menloparkbum: I've used all three of the languages you mention for relatively large web applications. People will say PHP sucks because it is ugly and retarded and only has one namespace. People will say Python sucks because of the whitespace issue and mod_python doesn't work on a $5/m shared hosting plan. Perl sucks of course because "the syntax is crazy!"  But, huge sites are built in PHP (Facebook, Hype Machine, Flickr, half of Yahoo!), Python (much of Google) and Perl (craig's list). In my experience they are all about equivalent except for aesthetic reasons.The headaches in a web app are usually at the user interface level (DOM/CSS/Javascript) and at the systems level (there's a bug in fast cgi! MySQL imploded!) and language choice gluing it all together is mostly a matter of taste. People with taste overestimate its importance. You can get pretty far in the internet biz with no taste (MySpace... originally done in COLD FUSION).That said, the most tasteful option out of your choices is Python.