Just wondering; I thought about it for a while and in my honest opinion I can't truly decide who'd win.  

Maybe on a one on one first time, Hulk will. I have a feeling in multiple battles, in the long run it'd be Doomsday. 

What do you think? 

Hulk

near-limitless physical strength depending directly on his emotional state, particularly his anger 

has durability, healing, and endurance increase in proportion to his temper

resistant to most forms of injury or damage

regenerative and adaptive healing

http://en.wikipedia.org/wiki/Hulk_(comics)#Powers_and_abilities

Doomsday

extreme physical strength

develop/evolve resistance from ordinary injuries

developed weapons and abilities that counters the powers of an opponent

immensely resistant to heat, cold, and conventional damage

inexhaustible stamina

highly accelerated healing factor that allows him to quickly regenerate from most damage

http://en.wikipedia.org/wiki/Doomsday_(comics)#Powers_and_abilities

(I know Wikipedia isn't the best to cite, but it's convenient)

(Also, I could not seem to locate a duplicate thread so pardon me if there ever was one)

Doomsday can't be destroyed so he'd obviously win. If I remember correctly, Superman had to send him to a dimension further in time to where the universe has imploded or something and no life could be sustained to finally get rid of that slab of rock.