One can both vendor and use the package manager to fetch updates. Just add the node-modules directory to your VCS.

The thing with node is that AFAIK it requires you to have libraries for what in most languages would be in the standard library. Maybe someone should start a "stdnode" project where the most popular / successful libraries for generic tasks are integrated into a dependable, maintained de-facto standard library, with an eye on quality and sanity, and community / Joyent funding.