Pylons provides a very productive development environment, similar to Ruby On Rails, by providing its own HTTP server. This means all development dependencies can be downloaded with a few commands, pages are automatically reloaded after editing Python files or templates, and there's even an AJAX debugger on the 500 screens. When an error occurs, you see a traceback like this:
By expanding one of the '+' symbols, a text box appears that functions as a Python console.
This feature allows you to inspect each frame of the Python backtrace, and even modify your application's state.
Useful Web Libraries
AuthKit is a plugin useful for authentication.
SQLAlchemy is an excellent SQL/ORM library.
Genshi is a powerful templating language that provides an XML-based template syntax as well as one geared toward plain text. It can generate HTML4 from XML, resulting in maximum compatibility for clients, while maintaining a tight XML pipeline on the server.