"Red Hulk" by Jeph Loeb and Ed McGuinness
I've never understood the appeal of the Red Hulk. In a way I get it - he's big, he's red, he's angry, and he's smart - but in another way he doesn't seem all that different from the "intelligent" or even "funny" hulks seen before. Back when Peter David was giving us a whole pantheon of hulks, the Red Hulk would have been beside the point. He would have been irrelevant.
Times change I guess. After the conclusion of "World War Hulk" (a great smashup), this Red Hulk appears, and heroes such as Iron Man, She-Hulk, and Thor must contend with the threat he poses. By the end of this TPB, the good ol' Green Hulk inevitably appears, the predictable occurs, and everyone goes on about their business as if the world hadn't almost ended (again).
Wikipedia tells me that Marvel also created a Red She-Hulk, and that this Red She-Hulk squared off against the original Green She-Hulk, who was not originally green but rather pink. I suppose that in time we'll see a Blue Hulk, or maybe an Orange Hulk, to compliment the Grey, Green, and Red Hulks already in existence. Perhaps Marvel could build the whole thing up into a gigantic "Battle of the Rainbow Hulk" event, thus giving the comic book world its first homosexual monster superhero.
That would be cool. I think.