Hulu, Twitter, Techcrunch, etc are written in Ruby.
Yahoo, Facebook, and tons of big social networks are written in PHP.
But what are some big top-name enterprise sites written in Python?
I am going to spend my time investing in either Python (w/ Django) or Ruby (w/ Rails) to create a data-intensive web application that has a personalization/recommendation tool (similar to Amazon).
Coming from a PHP background (OOP, Zend Framework), which would be best?