This is Williamsburg bridge. One of the first bridges I've crossed in NY and did it at night. There were interesting graffitis and art all around but you have to look for it. You can try to find one of Space invaders infamous work on the bridge :)
Brooklyn Bridge is a beauty and is one of the oldest bridge in NY. I have crossed the bridge once with my sister from Dumbo but also walked half of it from the Manhattan side twice to record HY and RH's wedding blessings. First time we went to shoot the video, we found out that we charged our battery overnight but the charger was not plugged in...fail.
BK bridge is a beautiful bridge to see and walk, although it is not super pleasant because it is always crowded with tourists and the occasional near hits with bikers that don't seem to care that you have wandered onto their bike lane. You can also enjoy the view of downtown Manhattan while breathing in engine gas from the cars swooshing below...
The George Washington bridge is huge, longer and newer. It is North-West of the island connecting Jersey and NY. It's super high and has a great view of the city of the entire city from far. When we crossed it that day in early January from Fort Lee, NJ, it was freezing but so worth it...for me that is, I think bf almost lost his ears.