Well, other than Scare moments and I guess VOIP isn't always built in, every other MMORPG has all of those things. Right? I mean, I played a lot of WoW and it definately fit the bill. I am not disparaging L4D's gameplay/story/immersion, but I didn't see anything special enough to declare "best PVE of all time". On the other hand, how much PVE story can you really create in EC other than "Tyranids want to eat everyone." Yes you can have some exposition and some background, but we haven't seen any of what they are already working on for that, so its hard to judge whether EC's existing (non-existant) story is good or not.