Ultimately, you are constrained by your environment. Each case is individual and must involve experimenting to find the optimal balance between frequencies and soundstaging. Away from the wall is generally better, with an unequal distance to the side walls and just enough toe in to achieve center fill and realistic soundstaging.
Question about speaker angle
I've always been under the impression that your front main speakers should be angled so that the "face" of the speaker is basically perpendicular with the listener's face when viewing the speakers from the sweet spot. I do however see others placing the speakers parallel or inline with the surface of the wall behind the speakers. I'm wondering, how much loss to the sonic sound stage this creates.