In my work environment I have three smaller monitors and love the productivity benefit. At home I have two 27" displays (the iMac and an external cinema display), but am having trouble laying them out on my desk so I can effectively use them without neck strain. What's the best layout for ensuring most of your work involves you staring straight ahead at your work, while still letting your work spread out over all those lovely millions of pixels?
EDIT: responses so far have focused on having the monitors at the right level, i.e. at and below eye level. But the problem I'm having is that just one monitor nearly fills my field of vision, so I end up turning my neck or chair dramatically to work on the other.