Metal Gear Solid 4. All those hours I sank into those games over the years. Brought a wee tear to me eye it did.
Final Fantasy VIII had a pretty epic ending too, preferred it to VII.
Modern Warfare 1 and 2 had endings that were both absolutely fabulous.
Portal was a great little surprise.
Red Dead Redemption was incredible,and had me feeling really down over the next few days. Me and John Marston had gone on this amazing adventure together, and to have had to do what you did... It was so sad. But what a great ending to a truly great game.
Mass Effect 3 by far!
I especially liked the black screen right at the end.
Red Dead Redemption