Metal Gear Solid 5.59
Metal Gear Solid 2 5.57
Metal Gear Solid 3: Snake Eater 4.00
There seems to be a downward trend here.
Maybe due to PS3 exposure MGS4 could beat MGS3, but I am not expecting it to do better than 2 or 1. I think this series has a "harder core" following in comparison to other franchises thus I don't think it's install base will accrue new patrons in a significant number.
"Let justice be done though the heavens fall." - Jim Garrison
"Ask not your horse, if ye should ride into battle" - myself