My favorite one thus far is the Williamsburg Bridge. This giant red caged bike platform is wide and splits into two sides on the Brooklyn half. It overlooks the subway tracks and highway below, and offers nice views coming back of midtown to the north and down town to the south. My only small qualm is when the path splits, the south path is technically for pedestrians only. Because of this they put rumble strips at the bottom, which is very annoying for bikers. As far as I'm concerend, pedestrians are not as important as bikers. I realize I have a long way to go until I fully consider pedestrian safety as important as my convenience, but I'm not quite there yet. It's probalby because pedestrians are so freaking unaware of their surroundings even when given adequate visual or audible warning. This is a topic you can be sure to hear more of from me later on. Regardless of this small inconvenience, my Billiesburg Bridge rating = 9/10.
I have tried the Manhattan Bridge once. It could be the best option if going to or coming from west Fort Greene area, but other than that it's narrow and the entrances are tough to find. It does offer a nice view down onto the Verizon baseball field on the Manhattan side, but other than that it's not the greatest. My bridge rating = 4/10.
I have yet to ride over the Brooklyn Bridge (although I have walked it), but I look foward to doing it when the opportunity presents itself. I almost did this when attempting to cut the 5 Boro bike tour down to 4 boros to save time, but I never even got to Queens due to the bottleneck at the entrance to the Queensboro and my overwhelming impatience. I also hear that the Verrazano Narrows Bridge offers pretty amazing views of lower Manhattan.