Basically, pandas, numpy, and matplotlib give me everything I could have wanted out of matlab from a numerical capabilities and graphing perspective.

In my opinion, matlab's excellent object inspection and debugging capabilities can be replaced with strict testing standards in your code-base.

On top of that, I get to use a whole slew of libraries that are non mathematically related -- frameworks for web services, accessing ftp servers, sending e-mails -- a lot of automated "utility" stuff.

And it is all "free". Fantastic.