First of all, comparing the two is kind of futile as many have mentioned since the games are so different and spaced apart so far temporally, but I will go ahead and give my answer.
MGS4:
MGS4 will have a greater affect on gaming history. OoT was pretty influential in terms of 3D Action/Adventure/RPG (I noticed this today playing Okami), but MGS4 trumps Ocarina in terms of storytelling and technical prowess. An over the shoulder the game really never felt so good and gave you so many options, including Gears of War and Resident Evil 4. I am in now way demeaning those games, but MGS4 definitely takes things a step further.
The fact that you can play through the game in so many different ways is simply incredible. I choose the stealth approach, but the action approach is equally viable. And blending the two works together perfectly.
Both are extremely important, but I think MGS4 edges out OoT in importance, and I have played OoT several times. OoT is epic, but MGS4 is legendary.
We had two bags of grass, seventy-five pellets of mescaline, five sheets of high-powered blotter acid, a salt shaker half full of cocaine, a whole galaxy of multi-colored uppers, downers, screamers, laughers…Also a quart of tequila, a quart of rum, a case of beer, a pint of raw ether and two dozen amyls. The only thing that really worried me was the ether. There is nothing in the world more helpless and irresponsible and depraved than a man in the depths of an ether binge. –Raoul Duke
It is hard to shed anything but crocodile tears over White House speechwriter Patrick Buchanan's tragic analysis of the Nixon debacle. "It's like Sisyphus," he said. "We rolled the rock all the way up the mountain...and it rolled right back down on us...." Neither Sisyphus nor the commander of the Light Brigade nor Pat Buchanan had the time or any real inclination to question what they were doing...a martyr, to the bitter end, to a "flawed" cause and a narrow, atavistic concept of conservative politics that has done more damage to itself and the country in less than six years than its liberal enemies could have done in two or three decades. -Hunter S. Thompson
