Thanks for the pointers. My goal is more knowledge than career directed -- it's a bit vague, but when I read documentation for projects like GSL or Octave, I get the same sense of awe that I had when I cracked my first book on C. I've also always been fascinated by digital signal processing and other such applications. Ultimately I'm driven to grok the domain. How I apply that knowledge is secondary to me at this point. :)