Does someone know some good C# GUI libraries (opensource / commercial).
I want to develop my own graphics user interface, probably something Acronis-like.
Skin support is welcome, but not necessary.
Thank you.
You should probably look into using WPF, which is built into .NET. It is an extremely extensible, flexible, and powerful UI platform that should give you more than enough flexibility to create an Acronis like UI (I assume you mean Acronis the company that makes backup software.)
Here are some useful links on WPF: