What is a good session store for a single-host Node.js production app?

I'm using Node's Express w/ Connect middleware. Connect's memory session store isn't fit for production:

Warning: connection.session() MemoryStore is not designed for a production environment, as it will leak memory, and obviously only work within a single process.

For larger deployments, mongo or redis makes sense.

But what is a good solution for a single-host app in production?