I used to go at the middle school when I first played Metal Gear Solid, the classic for PS1: it was the first time I said "wow a game can have a deep plot!". It was in a questionable Italian dub.
During my first job a collegue lent to me Metal Gear Solid 2 fors PS2, having contact with the voice of David Hayter actually helped my to express myself in English, thing that school was unable to.
But MGS3 was a gift from my father for my 19th birthday, I played it several times. Like above it was a way to perfect my spoken English (even thought with some slang...).
For these reasons this trilogy is very important to me.