Well, the title says most of it. I'm looking to develop a chat application that will hopefully become something more, and currently I'm considering my options for what I should build it on top of.

I've taken a look at Tornado with Redis as my primary option - Tornado, being a Comet server, is perfect for long polling to retrieve the messages on Redis, which I have the intention of using as both a persistent data store, as well as a message queue with its nifty subpub features.

However, I've also heard good things about Django, RabbitMQ, MongoDB and Orbited. JavaScript isn't a big problem for me, so Orbited's JavaScript support isn't too much of a boon.

Really, I'd probably be happy to develop on the route I've chosen for myself, but if there are any gaping deficiencies in my plan, I'd like some kind person to point them out before I find I've wasted months on this.