What is the most popular PS2 game?

There is no "most" POPULARgame and there are many games which are famous over the period of PS2:

But here is a list of the popular PS2 games:

God Of War I & II

Shadow of Colossus

Final Fantasy X

Final Fantasy X-2

Final Fantasy XII

Half-Life Ports

WWE Smackdown V/s Raw Series

Tekken 4

Virtua Fighter 4

Silent Hill 2

Resident Evil 4

ICO

Gran Turismo 4

Devil May Cry Series

Kingdom Hearts

Metal Gear Solid 3 : Subsistence

GTA : Vice City

GTA : San Andread

GTA III