Alex Mercer (Prototype) vs The Hulk?
From what I've seen of Alex, he's pretty freaking tough.
Here's some information on Alex Mercer. (From Wikipedia)
Alex's primary power is that of shapeshifting: he can control his mass, transforming himself into an arsenal of deadly weapons, such as turning his arm (in seconds, as seen in the new cinematic intro) into a large blade. He can also manifest other mutations such as huge, clawed hands, a long, sharp tentacle called the "Whipfist", or transforming his fists into huge hardened masses called "Hammer Fist" capable of smashing through tank armor. The fuel for these transformations is the biomass of fallen enemies that Alex absorbs in quick, graphic cutscenes. After killing a foe, the distinctive red-black tentacle mass that accompanies all of Alex's powers will burst from his body and drag the victim's form into his, consuming his memories and skills, and appearance along with his flesh. After consuming a foe, Alex can shapeshift to copy their appearance, allowing him to perfectly impersonate them. His powers can also change his eyes to allow him to see infection or traces of infected or to use "Thermal Vision" to see through obscuring smoke and other debris; however, this costs him some range of vision.
In addition to these shapeshifting powers, Alex is extraordinarily fast, agile and strong. He is capable of running at over 100 miles per hour, running up and across the sides of buildings, and jumping hundreds of meters. Alex is also capable of gliding. He is strong enough to easily grab and throw a car and eventually a tank as a projectile. He is also very durable and heavy, noticeable when he cracks the ground upon landing from great heights. Fire from an M16 assault rifle appears to do minimal damage to his body, but heavier weapons such as mounted machine guns, rockets and tank shells can cause serious damage to him, from which his body heals at a slow rate (in game terms) but he will quickly regain a larger amount of health by consuming someone. However, he can only retain a certain amount of biomass; if he consumes too much he must release it by using a Devastator attack. To further augment his durability, Alex can use his shapeshifting powers to transform his left arm into a huge, bony shield, or cover his entire body in armored plates, though he is slower in this form. These defensive powers can be combined with offensive powers for highly spectacular, destructive combat against the superhuman, zombified hordes of the Infected and the well-armed tanks, helicopters and infantry of the US military.
Even without shapeshifting Alex still possesses superhuman strength and agility. He can use a variety of kicks and punches, as well as more spectacular, gymnastic moves such as multiple "bouncing" tombstone drops, air combos, or sliding along the ground using an enemy's body as a surfboard.
Alex's most powerful moves are Devastators: huge, area-affecting attacks that use large amounts of biomass. Two Devastators have been seen in preview videos - one is an attack similar to the whipfist that sends dozens of razor-sharp tendrils shooting in every direction from Alex's body to impale or destroy all nearby foes, the second is a variation of the ground-spike attack, in which Alex shoves his biomass into the ground, causing dozens of gigantic pillar-sized spikes to erupt from the ground in an expanding circle around him, either impaling or sending everything above them flying.
And we all know the Hulk.
So who would win?