Sounds like you need to change from auto-area AF to dynamic or single (I use dynamic). It's on the back, right above the latch to open the CF card slot. The top is auto-area (the camera will select the focus point), middle is dynamic (you select, but if the subject moves from that focus point, it will still focus, or the bottom is single area (camera focuses only on focus point selected.
And, I have to say, with 51 focus points, I no longer find the need to focus and recompose. Though it was definitely a hard habit to break!