I've looked at matplotlib but still think it's ugly by default.
Compare to:
http://www.texample.net/tikz/examples/weather-stations-data/
http://www.texample.net/tikz/examples/rna-codons-table/
The beauty of tex font's + vector graphics is impressive. Try zooming in on the sparklines in the first example
I guess taste comes in place - I find producing good (as in academic publication good) figures in matlab an exercice of pain. The subplot mechanism is awful (at least was 5 years ago), and it is hard to control the layout. I heard mathematic is much better in that regard, but never used it myself.
Matplotlib (http://matplotlib.sourceforge.net/) is actually the best opensource library for creating great looking graphs that I have come across, and is comparable to Matlab and Mathematica.