In the security year that was 2006, zero-day attacks and exploits dominated the headlines. However, the year will be best remembered for the work of members of the hacking--er, security research--community who discovered and disclosed serious vulnerabilities in the technologies we take for granted, forced software vendors to react faster to flaw warnings and pushed the vulnerability research boat into new, uncharted waters. In no particular order, here's eWeek's list of <A HREF="http://www.eweek.com/article2/0,1895,2078362,00.asp?kc=EWNAVEMNL010307EOAD">five hackers who left a significant mark on 2006</A> and set the stage for more important discoveries in 2007.