Writing a 2D RTS game in C#: graphics library options?
.net, c#, graphics
Solution
The answers posted so far (apart from SDL.NET) have all just said to use OpenGL, DirectX or some variant of the 2. Personally, I wouldn't use either of these for a 2D game when you already have XNA. XNA already has some classes for doing 2D graphics (the main one being the SpriteBatch).
If you do use XNA, not only can you make a game that runs on Windows, but also one for XBox, Zune and Silverlight as well (Zune and Silverlight require that you don't use the 3D part of XNA though, but that shouldn't worry you). Basically, XNA will save you the trouble of writting all of the low level management code that DirectX or OpenGL need (such as handling window switching and a plethora of other problems).
I haven't used SDL at all, so I can't give you any personal opinions on it, but I have heard it is quite good for 2D graphics, so I'd recommend looking into SDL.NET or just going with XNA, the other suggestions here require a lot more work with little advantage (most people just want to make the game and not worry about the HAL interfaces and getting everything to play nice with the OS).
Problem
I am considering writing a 2D RTS in C#/.NET and i was wondering what options are available for a graphics library aside from XNA. What are they?