What game you can run is determined through settings, resolution, and framerate. If you require the most from all three, you will need to spend more money on components. As you reduce one or more of your expectations of each of these things, you can spend less. The 768p resolution is low enough to boost framerate on a budget card like the 460 quite a bit. The low resolution also means Ultra settings don't have as much negative impact. Of course, this all depends on the game itself and the framerate you find acceptable. Some people insist on 60fps or higher, others are more flexible.
As to what game to use as a showcase, that depends on what you think looks good. Rise of the Tomb Raider, Doom, and Witcher 3 are games I think look pretty great.