Recommendation on plotting library

[Andrew]

I was using D for some of the computations in my Bachelor's 
thesis paper, and I also looked into plotting in D. My conclusion 
at the time was there aren't yet any serious plotting libraries 
comparable to what's available in more popular languages, so I 
exported the data in json and rendered plots in Java. If you're 
already using python, it's probably best to keep using that.