There's already an open source competitior to matlab: python plus
matplotlib , sometimes known as pylab.

Sigh. It's really unfortunate that the Ruby/Python contention has
leaked into science. I had thought Python was sufficiently ahead in
terms of available libraries that it wouldn't come up, but maybe not.
(I would think that f2py alone was decisive.)

However, the issues Bill raises are very much the right ones, and we
should agree that these languages can be used in combination with very
large computing resources to open up new and better ways to do
scientific programming.

Michael Tobis
http://geosci.uchicago.edu/~tobis