Python is an excellent language for large or complex programming projects. Integral to programming in any language is making the code easy for the next programmer to read and maintain. It takes great effort to keep Perl and PHP programs readable. Where Perl gets unruly after 20 or 30 lines, Python remains neat and readable, making even the largest projects easy to manage.
For its readability, ease of acquisition, and extensibility, Python was recently chosen by MIT for students learning to program. In addition to readability and extensibility, Python offers much faster application development. For more on Perl vs. Python, see Eric Raymond's Why Python?.
In addition to easy syntax and substantial processing abilities, Python is sometimes said to come with "batteries included" because of its extensive library, a repository of pre-written code that works "out of the box".