I haven't played 4 yet so don't correct me if I'm wrong, but I STILL can't beleive they reserved the credit song for the PSP game. This was in my opinion the BEST song in the series and quite possibily one of the best songs ever written. "Calling To The Night" for Portable Ops, though I don't know who sings it.
If Snake truly does meet his "End" in Guns of the Patriots, then I think they should play this around his funeral. Or at least in the credits, play it SOMEWHERE. Is it on the "Ipod" item's list of songs? If anything, I think it'd be awesome if they just combined all the ending songs of every MGS game into one LONG credit sequence. But THIS one goes first.