wtf...i remember being in mgs3 the most and not at all in 2. particularly the ending of the 3.
Well i disagree. I only remember it used at the end of MGS3.
Regarding MGS4 music, i guess it was good, but never did i felt impacted by it. I guess some, if not most, will like it that way, as they don't like the music to "force" their emotional engagement, because music can be used as a sort of emotional guide.
Personally, i love it when the music makes itself very present, when the music is the embodiment of what you are seeing, more than being an "auxiliary", i love it when it knows its present, and it wants to be amazing, and when you close your eyes you can see the music shape the scene. In games this kind of music it's much more complicated, as you connect it to gameplay sequences.
"Iconic" themes, or memorable themes, are very important to me, but they aren't "crucial". But i don't remember one piece of MGS4's music, and i've played that game 3 times now.