Totally FF7 all the way!
I've payed sort of Post Apocalyptic game... In Guild Wars, these monsters make a bunch of meteors rain down from the sky and destroy the kingdom of Ascalon. It's not all over the world, though, but I've never gotten farther than Ascalon...
I don't really like "Apocalyptic" stuff, cuz, like Undead described, its usually just a big wasteland with tons of rubble and crap like that. BOOOORRRIIIINNNNGG!!
Final Fantasy 7 would be awesome, cuz you could join SOLDIER and get super strength and use huge swords and ride uber awesome motorcycles, and have funky hair, and fly up and slice up some Bahamuts, and maybe even fight a Sephiroth clone. BOOYA!
Or better yet, become something like Vincent! I mean seriously, who wouldn't want to be able to fly, turn into a wierd invincible cape thing, or mutate into some sort of demonic monster!?!