Meteor.js and Mongoose Compatibility
Unfortunately, there are problems. We've wanted to do the same thing, but (out of the box) the mongoose package doesn't use Meteor's DDP protocol, and won't trigger the reactivity when you do CRUD operations. There may be also issues with Fibers/etc, although we haven't pushed with Mongoose enough to find them.
The good news is that (server-side) Meteor watches the db for any changes, DDP-induced or not, and will pick them up in about 10-seconds or so. It will then publish them to the clients, which will pick them up in standard meteor format.
We've been looking for a mongoose-ddp-meteor package to solve this issue, and might have to end up building one ourselves.
EDIT:As of December 2013, Meteor's Mongo package listens to Mongo's oplog, and will reflect any changes done by external mongoose activity in real-time.