How can I install NumPy / SciPy on Lion? Macports?
Binary?
RVM-esque tool?
Other?

I will be using NumPy/SciPy for a computer vision project, so I want to do it once and do it right.
do it with the scipy superpack, by Chris Fonneback. It's very easy, automated and it works (using it right now!).

It also takes care of installing Fortran for you, which is mandatory for the python libraries to work.

PS: If you have Lion, Numpy is already part of it.