Well, I guess the first question will be whether or not the white background is such a great idea. Just because it comes close to real paper and we can find everywhere on the Internet these days doesn't necessarily make it a good (or may I say perfect) choice.
I remember that (many many) years ago we only had the yellow-on-black "colour scheme". And I also remember that it wasn't that bad. It didn't have that contrast as black&white. Not too long ago I learned that it is also better to the human eye.
Sometimes I really wonder who designs the colour schemes that, e.g. get shipped with operating systems. I usually ignore them, but I remember seeing really awesome mixtures of pink and green and whatnot. Well, I don't do drugs...
There are some studies about what colours do to your subconsciousness (calm down, cause aggressions, ...). I'm thinking that the commonly used colour schemes are somewhat based on that. Maybe they just added readability. Coding shouldn't be a suicide mission.
But as far as the colour scheme of current IDEs is concerned I'm fine with it. Let's face it: the simple idea behind it is to make it easier to find something that's different from the general "code noise". And to be honest I don't really care what colours they use to allow that. It just shouldn't hurt my eyes or burn parts of the code into the back of my head, like a glaring red on some tone of green.
Coding should be relaxing. And that's what it is to me.