Metal Gear Solid (PS1) is my favorite game of all time. Here are the rest of my personal favorites, in no particular order:

Metal Gear Solid 2: Sons of Liberty (PS2)
Metal Gear Solid 3: Snake Eater (PS2)
Super Mario Bros. (NES)
Super Mario Bros. 3 (NES)
The Legend of Zelda: A Link to the Past (SNES)
Super Mario World (SNES)
Contra (NES)
Paperboy (PC, NES)
Sonic the Hedgehog 1-3 (Genesis)
God of War (PS2)
Resident Evil 1-4 (PS1, PS2, GC)
Star Wars: Battlefront 2
Grand Theft Auto franchise (PC, PS2)
Medal of Honor franchise (PS1, PS2)
Guitar Hero (PS2)
Max Payne 1 & 2 (PS2)
The Godfather (PS2)
Syphon Filter (PS1)
Syphon Filter: Dark Mirror (PSP)
Lumines (PSP)
SOCOM: U.S. Navy Seals Franchise (PS2, PSP)
Street Fighter II (Arcade, Genesis)
Final Fight (Arcade, Genesis)
Golden Axe (Sega CD)

Good Lord, so many more to mention. I'll add some more as I remember them.

"Growing up my dad was like 'You have a great last name, Galifianakis. Galifianakis...begins with a gal...and ends with a kiss...' I'm like that's great dad, can we get it changed to 'Galifianafuck' please?" -- Zach Galifianakis