The pre-4 Resident Evils kinda suck in retrospect. In addition to all the stuff that we knew was terrible (e.g., voice-acting) the controls and inventory system are incredibly dated. RE2 is the only one that holds up well, and maybe Code Veronica.
I was never all that fond of MGS either (I haven't played 4). Outside of boss battles the gameplay is mediocre, and the storytelling is ridiculously melodramatic and self-important. You ever meet a stoned college freshman who's just taken his first philosophy class, and is trying to blow your mind with these trite ideas that he thinks are earth-shattering? That's MGS.
COD4, on the other hand, is easily the pinnacle of that series. There isn't much difference between the first three, fanboy ranting about 3 aside, but IW stepped up in a big way. Weapons, level design, gametypes, perks - pretty much everything is better.
