We use MongoDB pretty heavily at work (along with Postgres and an in-house db), but I haven't found a good data browser like you get in Futon for CouchDB. There's a port of Futon to MongoDB, but the data models don't quite line up and I wanted something read-only and simple. I went ahead and wrote such a one in Python using the Aspen web framework. I'm calling it Mongs, after a local dairy. Check it out if you want a nice clean Python-based data browser for MongoDB.