John Backus
I've seen the obituary for John Backus earlier, but my brother emailed it to me as well with the comment that this is probably the last year he'll teach FORTRAN to his Chemistry students, probably in favor of Java. Somehow fitting, though I asked him to reconsider his choice of language. I should have pointed him at PLT and Doug Williams' science and simulation packages.
You need the willingness to fail all the time, you have to generate many ideas and then you have to work very hard only to discover that they don't work. And you keep doing that over and over until you find one that does work.