* haproxy - frontline proxy * nginx - static files and back proxy * supervisord - service uptime * gevent/meinheld - wsgi * django * gevent/eventlet - websockets/comet * postgresql - Database obviously * memcached - caching for django * rabbitmq - message queuing * celery - message processing * fabric - deploying * hudson - building
The only things I would add are "solr" for search, and "redis" for miscellaneous speed improvements, such as statistics tracking and counting.
