PS3 uses opengl for the most part, but there are middleware just for those DX9 -> Opengl situations. The 360 also uses DX9.

DX10 cards are aplenty so I would consider even some DX10 features for sake of PC group which is not exactly plenty at this point.

DX11 is kind of a waste, as it is very "not" popular from a business standpoint. You care barely see a DX11 capable card in most PCs out there...though with FF14's PC requirements..probably a good chunk.