Depends on how much you want to spend on it, there are a lot of options, we do a variety of work in 3D graphics and have explored it extensively in the past
Below I have provided some links to help you get started
3D scientific graph from Gigasoft - http://www.gigasoft.com
Ginosurf from Gino Graphics - http://www.gino-graphics.com/products/surf.htm
Matlab builder for .Net - http://www.mathworks.com/products/netbuilder
Meshviz and OpenInventor from Mercury Systems - http://www.vsg3d.com/
There is always Directx and its ports to managed code
Hope this is useful
