I am the author of nano. When starting with CouchDB I did exactly as Jason Smith advised using Mikeals request library. Nano was born out of using that code in production and realizing I had some coded that could be improved and abstracted.
The end result is minimalistic and you still have a way to go down to the request level and do a request (which many users do).
Nano was really well accepted by the CouchBase team, mostly cause it's soo\ simple and maps well to the API.
If you are interested in checking out more check out this blog post:
http://writings.nunojob.com/2011/08/nano-minimalistic-couchdb-client-for-nodejs.html
