HI -- First thing to remember is -- you do not live in the hall , you just pass through it. You cannot really make it wider but you can help it appear shorter and wider . Paint the end wall a dark color like a charcoal/black and hang an interesting art piece , this gives the eye a destination . Have a hall rug runner with a side to side strip , this will visually shorten the length . Then paint a color that is no darker than a medium tone . You could do the hall in an all dark color , then use the hall as an art gallery with the most colorful painting at the end to draw you in . Keep the art displayed larger with either color scheme .

You could make a feature of a narrow room. We had a similar hallway leading into the kitchen which was plain and nondescript, so by putting darker colours at either ends it drew the eye, and brick wallpaper made it a really interesting space. We're planning on putting some artwork in the centre but something like this could work for your hall if it's to your taste.

I say keep the white, but hang some pictures.

Large mirrors also make hallways seem a lot more spacious than they appear :)