That being said do all of the different displays, LCD, CRT, Plasma, DLP, etc, all require shielded speakers next to them or is there a type that does not?
Most speakers are shielded anyway. I know that my studio monitors that are being used in my home theater setup are shielded. Even on a CRT RPTV base set, the guns are so low to the base, I wouldn't think that the speakers will effect the picture. I could be wrong.
I won't say that magnetic fields are immune from affecting all electronic devices, because theoretically they could do so, but only CRTs are affected. CRT tubes drive an electron gun, and the beam of electrons are controlled in their scan sweeping by magnetic fields generated by electromagnetic coils in the display. Outside magnetic fields from speakers or other equipment will disturb this.