#1 Eddie Guerrero
Former WCW Cruiserweight Champion, "Latino Heat" Eddie Guerrero signed on with the then-WWF in January 2000 as part of the Radicalz with Chris Benoit, Perry Saturn and Dean Malenko.
At just five feet six inches tall, Guerrero didn't measure up to Vince McMahon's ideas of a headliner.
Despite that fact, Guerrero enjoyed early Championship success in the company winning two European titles and one Intercontinental strap within his first 15 months in the company.
However, he was soon sent to rehab amidst concern over an addiction he had developed to pain medication. However, following a drunk driving arrest, he was released from the company.
Guerrero returned in April 2002, immediately making a splash by winning his second IC strap from Rob Van Dam at Backlash 2002.
However, 2003-05 would be the greatest period of success in his career. Guerrero adapted his character to become a likable cheat and got over huge with the WWE audience which led him to the WWE Championship when he shockingly defeated Champion, Brock Lesnar at No Way Out 2004 before defending the strap in a featured match at Wrestlemania XX versus Kurt Angle.
Unfortunately, Guerrero struggled with the responsibility of being Champion and campaigned to lose the belt, which he did versus John "Bradshaw" Layfield in June, ending his reign at four months.
Guerrero spent the majority of 2005 in a long-running feud with Rey Mysterio before he was scheduled to defeat World Heavyweight Champion, Batista for his second World title before he was tragically found dead in his hotel room at the tender age of 38.
However, despite his untimely death, Guerrero's legacy was secure and he was inducted into the WWE Hall of Fame the following year.