Hard list to make, as it constantly will be changing depending on my preferences at the time, not to mention new titles.
1. Metal Gear Solid 3: Snake Eater
2. Final Fantasy VII (Although I have yet to try VI, heard it's great)
3. Metal Gear Solid
4. Kingdom Hearts 1/2 (Sure, they're two games, but oh well)
5. Galaga (Because arcades need love too)
But there's a rough estimate.