Unigine's Heaven Benchmark tool is a popular one being built around DirectX 11 and taking advantage of all the fancy features the latest graphics cards offer. The developers have just rolled out version 2.1 which brings two significant adjustments with it along with some general stability fixes and improvements.
The first one is support for OpenGL 4.0 which is an API that technologically rivals DX11. 2.1 will use all of the advanced features OGL4 is capable of (incl. hardware tessellation).
The other change is that stereoscopic 3D is also now available for people with supporting equipment. There are now several stereo 3D viewing modes selectable such as Analygraph, separate images, 3D Vision, and iZ3D.
Head over to Unigine's website to grab it. It weighs in at 231MB.