Direct X 10 will contain new features:
The most important for the GUI is of course the removal of the old way of rendering Windows, and instead replacing it with a Direct X rendered environment, they've called:
Windows Graphics Foundation (WGF)
SHADER MODEL 4:
UNIFICATION OF SHADERS:
Unification of shaders (Vertex and pixel will become non-existant in the ways of now. As a game needs a certain function, the pipelines can change to one or the other)
GEOMETRY SHADERS:
Geometry Shaders will be added allowing new advanced surfaces to be created. for example B-Splines and subdivision surfaces.
This will allow for curved surfaces where curved polygons are used. Know what that means? Basically a car wheel will look completly round. No more jaggedy octagon effects.
FULL RESOURCE VISUALISATION:
Full Resource Visualisation, another new feature will then banish limits with Video RAM size and maximum shader lengths.
The graphics card will be able to see its entire memory space, and request chunks of it when required, so only bits of textures needed will be loaded at one time, and not the whole map.
GPGPU:
In the future, we'll also see graphics cards carrying out physics Nvidia says (They call this the GPGPU - A card which can also carry out non-3D type jobs), which can do this much faster than the CPU, and may make cards like the Physx unit, most likely much less needed.