I'm not sure if this has been mentioned,
But there is a distinction here. This card will support shader model 5.0, which is introduced with DirectX 11, however dx11 is backwards compatible with DX10 hardware*. (DX10 hardware uses shader model 4).
The big thing is DX11 brings compute shaders to the table. They are similar to pixel shaders, however instead of dealing with textures and drawing to a render target (eg the screen), you are dealing with reading/writing more general memory buffers. Compute Shader 4.0 will work on DX10 generation hardware, but it's quite limited in comparison to 5.0.
Just like DX10, the new features don't make any significant new effects possible, they just make them much more efficient (and therefore, far more likely to be implemented).
A simple effect like a box blur is *way* faster with compute shaders.
The other change, is that D3D11 has deep support for CPU multithreading optimization. No matter what, you still need the CPU to tell the graphics card what to draw (this is done through what is known as a command buffer) - D3D11 allows these to be built on different threads before being combined and sent to the video card, it also allows resources to be loaded on multiple threads a lot more efficiently.
------
I personally think it's getting to the stage where most PC developers will move to DX11. It makes more sense than DX10 as there are more significant benefits and with Win7 about to come out. Supporting XP users or old cards really won't be cost effective. In a year or so I'd expect the majority of PC games will be DX10/11.
* I'm not sure if it's 100% of DX10 hardware, certainly the vast majority...
