For improved computer posture, avoid drawing your feet toward your back.
More than position, this tip is about avoiding the tendency to draw the body together. When sitting at your desk, allow for ease between your lower legs and your upper legs. By allowing your feet to rest gently on the floor without pulling them toward you, you may find that your back will settle more comfortably against the back of the chair.
More on Computer Posture:
Video: Improve Computer Posture
For Seated Bending, Lead with Your Head
For Seated Bending, Use Your Hip Joints
There are more resources available on the Free Your Neck Blog. Please write your requests in the comment section.