Okay, hmmm... I'm gonna go with the original Metal Gear Solid. First of all, it was a good and decent piece of work. It got the whole tactical espionage thing going alright, and Snake was a proper badass. But there's more to it than that. The first MGS also had the fun of there being so much material to make fun of or spoof and parody. Granted, you can do that with the rest, but MGS is the most FUN to make fun of. People quote Genome Soldiers, make tons of references to the Box, use the codec and "!" noise all over the place, etc. - just for kicks. There's alot of material in there. Has anyone even THOUGHT of the manner in which Foxhound members seem to be set up like Megaman X villains? (Hah-hah! They used the Konami Code to steal from Capcom!) And then, of course, there is the Awesome work of a man called Egoraptor. But I digress... The other games have their amusement quotient, but not in the same levels as Metal Gear Solid the 1st.