Might & Magic VI: The Mandate of Heaven.
At least 7 times through it after doing all side quests I think, last time in late 2010 after I found a site that sold it through digital distribution (CD wouldn't install on Vista). The graphics are obviously crap, but they were already subpar when it came out, which is why - unlike a few other older games - it doesn't bother me the slightest I think; it never factored into me liking it in the first place, and thus it has everlasting staying power.
Other than that, God of War has seen a few replays, and will undoubtedly see more.