How to get the best picture quality

[Shonumi]

It depends on what you're looking for and what your GPU can handle. You're still only using a form of MSAA with CSAA. That only deals with geometry aliasing (e.g. the edges of polygons for example) but things like shadows are unaffected. You can use other types of AA such as FXAA or SSAA to deal with more forms of aliasing. OpenGL has 4xSSAA, and it does a pretty good job of providing a clean image if you set your Internal Resolution high enough. Be warned that as you increase your Internal Resolution, SSAA gets more and more demanding. FXAA provides less IQ improvement than SSAA, but it's very light on GPU resources, although some people find FXAA to be "fuzzy" or "blurry". If your eyes find it acceptable, then you can use that if SSAA is too taxing for the Internal Resolution you want to play at. Also note that FXAA was added recently, so use the latest development builds if you want to try it as a post-processing shader in Dolphin (your drivers can probably force it in any application anyway though). I see you also have your Internal Resolution set up to 1x. You should increase it to 3x or 4x if your GPU can handle those resolutions when you apply whatever AA you want.