The Pacquiao-Mayweather fight.
Fans want it. Boxing will benefit enormously. A lot of people - certainly the fighters themselves - stand to make a lot of money.
Regardless of whether or not this fight will actually happen, it's a topic of much speculation, discussion, and even polls (an LA Times one has 77 percent voting that Pacquiao would win).
But will this dream match ever happen?
Both fighters aren't that old; Floyd Mayweather is 34 and Manny Pacquiao is 32.
Both fighters are active in the sport and have fought in 2011.
However, both fighters have little to prove in terms of reputation and wealth. Mayweather has his perfect record to worry about. Pacquiao has taken an interest in politics.
And then there's Mayweather's rant after his recent victory over Victor Ortiz.
I don't need Pacquiao. Every time Floyd Mayweather goes out there, he's going to make over $70 million, he said.
I don't need him. Where was Pacquiao in 1996, 1997, 1998, 1999, 2000, 2001 when I was dominating the game? He never asked me when I was in my twenties or when I was in my teens, he said.
Mayweather has also made constant innuendos that Pacquiao takes performance enhancing drugs. If the two were to ever negotiate a fight again, Mayweather will insist on extremely stringent drug testing procedures, which Pacquiao and his camp have rejected in the past.
On the drug testing issue, Mayweather accuses Pacquiao of not stepping up and Pacquiao's camp has accused Mayweather of using it as a tactic to avoid the fight.
Whatever their real motives, both sides have excuses and seem unwilling to yield to the other side's request in order to make the fight happen.
Both fighters aren't getting any younger. The longer the standoff drags on, the less likely the fight will ever happen.
If it doesn't, it'll be a real shame for boxing and its fans.