I really wish there were two "white" values that were software accessable. To comfortably read black on white text, I turn my backlight down, but to watch a movie, I turn it up. This makes sense because, presumably, the brightest thing in a movie will be brighter than a piece of paper...
So basically you want movies to be treated as high-dynamic range content while most applications are treated as having a lower dynamic range so #FFFFF will not be the max brightness of your monitor. I think this is the direction we are moving in with HDR monitors and may already be how some operating systems work (except maybe the part of treating non-HDR movies as having a higher dynamic range than standard applications).
I don't have HDR content nor HDR displays, so, I suppose I want something lower than standard (LDR?) for "office" content, and I want the lower dynamic range to be accomplished by lowering the maximum brightness.
I first noticed this with some video games (Maybe Hexan or Quake?) versus Word 2.0; however, back then my monitor had brightness and contrast knobs on the front so it was trivial to switch (IIRC, brightness adjusted black-level, contrast adjusted white-level).
