I would like to keep firefox as my system default browser on my Mac, but launch IPython Notebook in Chrome[1].
This answer led me to my ipython_notebook
On OS X, you can put the following in ipython_notebook_config.py to open Chrome:
c.NotebookApp.browser = u'/usr/bin/open -a Google\\ Chrome %s'
The executable in '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome' fails for me with 'unable to obtain profile lock', so going through 'open' is the only simple alternative I see.