As for why it is blank, the xserver is supposedly smart enough to figure out which video card driver, proper resolution, keyboard, etc on its own without any user intervention. This means you are stuck with whatever resolution the developers thought you might like.
In my case my hardware is old enough that this process doesn't work and I have to have a xorg.conf with the 2 resolutions that my monitor supports. I just change my xorg.conf and restart x when I need to change resolutions. Switching inside X is a good way to freeze my PC.
You might be able to fix it by adding something like the following into your xorg.conf