Your list appeals to my inner geek. However, I suspect they are not the 10x multipliers in my practice. I may make an exception for knowing regex's and perl ver

Your list appeals to my inner geek. However, I suspect they are not the 10x multipliers in my practice. I may make an exception for knowing regex's and perl very very well. My contribution to your list is a skill that I would really really like to have: the art of approximation. Specifically, in the style of Sanjoy Mahajan's book, Street-Fighting Mathematics: The Art of Educated Guessing and Opportunistic Problem Solving. http://web.mit.edu/sanjoy/www/ http://web.mit.edu/sanjoy/www/ After reading that book I have been slowly trying to accumulate approximation methods and metrics in whatever I read, in order to estimate and validate quickly.