I've put almost 120 hours into Oblivion as of this writing. The game is simply a masterpiece. Bethsheda Softworks used Pixel and Vertex Shaders throughout the game, in the grass, in the armor, in the water, in the architecture. Further, they used HDR in almost every scene with realistic lighting throughout the game. The X1900XTX plays the game well up to 1280x1024 with 4x AA 16x AF and HDR enabled.
The first game that I played on a console was the first Tomb Raider on the Playstation console many moons ago. Eidos has released new versions of the Lara Croft game every couple of years. The last game in the series, Angel of Darkness, controlled horribly and I never got into the game. This year Eidos has released their latest incarnation, Legend. The game played well on the X1900XTX.
Another classic game was the original Prince of Persia. The first time I played Prince of Persia was many years ago on one of the early computers I had. Ubisoft released Prince of Persia Warrior Within a couple of years ago, but the game was one of the first to use Pixel Shader 2.0 effects. The game plays absolutely perfectly on the X1900XTX, with maximum resolution, AA and AF settings totally playable.
Game screenshots