Well the odd thing is MGS2 is virtually worthless anyway. It sells for 2 pounds on the high street.
MGS2:Substance is 12 quid.
I just remembered some more good ones, I have Pokemon Snap, Pikmin 2, Twilight Princess GC and Shadow of the colossus all with the official seals on them. I saw the pokemon one go for a hundred quid sealed about a year ago, I only bought it for a fiver.
Anyone upset about the sealed nature, I have played through all of those games anyway. They were all for investment purposes.
Another favourite of mine is Super Metroid with the Large box on the SNES.