Richard Hipp is THE most down-to-earth person I've seen whose also a software engineer. I just watched a video of his talk on SQLite, his embedded SQL engine in a C-library.
Google Video: Hipp on SQLite
Watch the video, read up atleast a part of the stuff on SQLite.org and SQLite on wikipedia and don't fail it to try it out, atleast at the sqlite commandline program. And you'll know what I mean.
But most of all, it is the simplicity of the person that awes me. If I wrote something like that, I'd be conceited as hell. Maybe, I'll never get round to doing anything cool. To top it, his program is Public Domain not even GPL. Which means he doesn't care who uses it, what they do with it or if they even tell him about it, as long people use it. In the video, he cites the example of all these companies that got to him to accept small sums of money and sign on a piece of paper that the program is actually free of a license.