hmm, never used it myself, but im pretty sure arnold is an offline renderer. You also have Keyshot for realtime rendering. Also, Vray (and MR?) have realtime rendering options available? RT and iRay i believe they are called.
Gheromo, it looks like the link you sent me are for the company that makes Arnold, which I've heard great things about also. I wish they would make it for Max but since I plan on learning Maya anyway, it's worth it to have a look, thanks. @JohnnyRaptor, yeah it looks like Arnold is the plugin made by Solid Angle which…