Depends on your tastes. If you like platformers the PS2 had some great ones. Jak and Daxter, Ratchet and Clank, and the Sly Cooper series to name a few. For something more action-oriented the old God of War games still hold up, although they are very different in tone from the modern ones. If you have any interest in JRPGs there's FFX, X2, and FFXII along with Personas 3 and 4. Although most of those have better ports/remasters/remakes on modern systems.