You should at least try nginx/gunicorn (http://gunicorn.org/). And if your clients are constantly pinging and the data hasn't changed, make sure you are caching it in memcache (etc) to relieve the database.
Honestly, I'm a little scared of using something like gunicorn. I could be wrong, but it seems like an extremely new technology, especially when compared to Apache, which has a lot of history behind it.
http://ericholscher.com/blog/2010/aug/16/lessons-learned-das...