well I lile Python because it is good enough at most things to be useful and it is fast to write. It also has a great library support compared to the other languages that I have used.
The majority of my work is limited more by my time than processing time, so things like multiprocessor optimization and weird data structures aren't really things that I have to worry about. I might put 500-1000 hours into a project that only gets run for 25 minutes every other week.