Had an issue with NPM not found with an install of Node.js via NVM. Tried $ which npm and that didn't return anything. As much as I like a puzzle sometimes its easier to start again, so here is how to clear out all the files for a fresh install:
$ rm -R ~/.npm
$ rm -R ~/.nvm
$ rm -R ~/.bower
Then head back to github.com/creationix/nvm and install again.
Don't forget to add nvm alias default 0.10 to make sure NPM/Node is loading with each new terminal window.