[onion2k]

A couple of obvious exceptions are John Carmack (for 3D graphics algorithm design) and Linus Torvalds (for OS design), although whether or not they contributed to 'computer science' rather than their particular software domain is debatable.

[pharaohgeek]

I would argue that Torvalds merely built upon already established OS principles, rather than being a pioneer in OS design. Linux, by design, is nothing more than an open-source UNIX equivalent. There's nothing wrong with that, of course. It's just not some groundbreaking work. I completely agree with Carmack, however.