I would try to use potable devices like iPad/Kindle/Mobile more for reading (Hacker news etc) purposes. Most of the time we don't need a full fledged computer compromising the sitting posture.
Do you find that you read better with a mobile device? I tend to find myself adopting awful posture when using any mobile device. With my computer and desk at home, though, I've got a monitor and keyboard at the right height and a very comfortable chair where I can maintain appropriate posture.