#3: Randy Couture:

Few fighters manage to win titles in two different weight classes. Then again, few fighters can compete at an elite level once well beyond 45 years old. Obviously, Randy Couture is not your average man; he’s Captain America, dammit.

Throughout Couture’s career he faced any and all put in front of him. Never one to turn down a fight, Randy battled Tim Sylvia, Pedro Rizzo, Chuck Liddell, Vitor Belfort and Tito Ortiz, all in winning affairs. Amazingly he fluctuated between light heavyweight and heavyweight seamlessly, and despite being an undersized heavyweight, it didn’t prevent him from capturing the title.

After a devastating knockout loss to Lyoto Machida at UFC 129, Couture finally hung the gloves up.

#2: Georges St. Pierre:

“GSP” has been an absolute phenomenon, and in all honesty, may be the most athletic fighter to ever enter a cage. An unchallenged fight IQ and insanely diverse skill set separate Georges from nearly every other champion the sport has seen.

Throughout Georges’ nine year career he’s toppled every opponent he’s faced. From the legendary Matt Hughes to elite challengers in Jon Fitch, BJ Penn, Josh Koscheck and Jake Shields, St. Pierre has emerged successful time and again.

Though St. Pierre suffered a hiccup at UFC 69, when he was stopped by Matt Serra, he’s been flawless since; he’s also avenged that loss, in brutal fashion.