Although many refuse to admit it, Tom Dwan is quickly becoming one of the best at MTTs too. Although no wins yet, he has some very deep runs and will soon break the no-bracelet-streak. When it comes to cash games he is only second to Phil Ivey but he can still surpass him in a few years. Not only at NLHE, but PLO and mix games too. I'm really looking forward to Ivey vs Durrrr HU for 50k hands!
So, Ivey's no.1, Dwan second. But there are so many great players that it's really hard to compare them. I guess Dwan is second just because he made shitloads of money faster than everyone else.
Negreanu is one of the best in the world, but if you put him in a NL or PL game at the table with Dwan, Ivey and Antonius he'll get crushed crushed crushed!! Negreanu makes money of PokerStars, Phil Hellmuth and the loose cannon on TheBigGame.
One thing to keep in mind though is that when the greatest play each other it's more to prove their skills. They make money from worse players, drunk fishy rich people and sponsorship deals.