The people who I work with whom I regard as great hackers work almost exclusively in the real time embedded space (industrial automation systems) and don't have web notoriety.

Slightly more prominent individuals could include Ted Neward (http://blogs.tedneward.com), Joe Duffy (http://www.bluebytesoftware.com/blog/default.aspx), James Devlin(http://www.codingthewheel.com/archives/how-i-built-a-working...), and Dustin Campbell (http://diditwith.net)