ipython + numpy with a little matplotlib is my weapon of choice...but in the past I used to use Matlab (kinda weird it's not listed with the other gui's or a option)
I really just use nano/pico from that poll list and I guess notepad in Windows. But, normally these days I use jed to write python scripts and it's very good. If you find yourself not a vi or emacs fan try it.
http://www.jedsoft.org/jed/
Well...
If textbooks count then I am in the 10-20 range...but I do read plenty of articles/journals on the subways.
Otherwise I am just addicted my Nintendo DS lol.