Dude, all i have to say is, I've been a MGS fan for years, I played most if not all of them (minus the first 2 or 3 that came out when I was 6). But I think the graphics and game design, and story, all written by Hideo Kojima are sick. Best plot to any video games ever. A very very very distant second is Half-Life.
But, I agree. Plus, Raiden is one of my favorite characters.
(Little tid bit of information for you: at the end of MGS4 when Drebin talks about how he was a child soldier in Liberia or whereever, and was given a gun at 6 years old, well that is Raiden's background as well. So Hideo makes it seem like they were both in the Small Boys Corps together. Sickness.)
Plus, if you have not already, I SERIOUSLY recommend getting online and downloading the MGS4 Database/Encyclopedia, it tells everything from all of the games. Plot lines, timelines, et cetera.