Although not as handsome as its older sibling the Brooklyn Bridge, The Manhattan Bridge is much better for commuting. The Brooklyn Bridge has one walkway with a line down the center, bikes on one side, commuters on the other. However, the throngs of tourists spill into the bike lane, causing an enormous hazard to bikers (and themselves).
On the other hand, the Manhattan bridge has separate walkways on either side of the span -- Bikes on the north path and walkers on the south path.

Looking west toward Manhattan:

On the left of this picture (facing west, toward Manhattan) you can see the D train rumbling past: