You can turn off graphics.PreferMultiSampling = false; typically in initialize when after the graphics device is set up.
In addition to setting the SamplerState. you can create your own states then just pass them to the graphics device. This usefull especially if your drawing quads or primitives.
For instance you might toggle a bool when the s key is pressed such as showAnisotropicOrPoint.
GraphicsDevice.SamplerStates = SamplerState.AnisotropicClamp;
GraphicsDevice.SamplerStates = SamplerState.PointClamp;