I don't think realism has to be dull. Who knows what sort of visual effects would accompany movement beyond light speed? Perhaps the stars wouldn't move, but there might be some interesting video effects. Your screen colors might polarize for a second every so often, or your viewport could pulse multicolors. It might even be something as simple as the slight blurring of text, occasional static bursts, etc. I'm sure the visual effects crew could come up with some fun things to do.