Patek Philippe Golden Ellipse
Speed is the chronograph mode, but is combined with a tachymeter scale to help you estimate speed. This is done by using two relative mile marker points (or other distance markers perhaps) in combo with the chronograph. Basically you measure the time it takes for you to go one mile, and a scale will tell you the speed digitally in the watch. I am sure this function can also be used as a normal chronograph.
[Ed. note - I loved wearing and photographing this piece. A great dive watch. Simple good looks with AP quality. Like Meehna said, not cheap, but not still lower on the AP range of prices. Great daily wear.]