Oblivion looks absolutely stunning with HDR and MSAA enabled. The game is able to play at a decent resolution with those settings enabled, however. Oblivion can be played with lower settings if the system isn't up to it, and I would suggest perhaps 1024x768 4x AA 16x AF is fine throughout the game with a X1600XT with HDR enabled, not bad for a $172 video card. Oblivion is a RPG; therefore framerates are not as important as on a FPS game like Quake4.
Quake4 was the latest game from iD Software. The first Quake was also the first OpenGL game with GL-Quake. Playing that on a Voodoo1 was a joy. It was a night and day difference between the graphics of Quake and GL-Quake. The EAX1600XT can play Quake4 with little trouble at a medium resolution of 1024x768. Ghost Recon Advanced Warfighter is the latest game in Tom Clancy's Ghost Recon series. Sporting a new graphics engine with advanced Pixel Shaders and Vertex Shaders, GRAW is an excellent example of the modern game. The X1600XT plays the game well, with full visual fidelity intact.