My wife and I stayed in a 4th floor concierge room overlooking the Boardwalk back in August of 2001 (sorry, don't know the room number), but it was directly over a bakery I think.
The room had a balcony w/no chairs, but we just took the chairs out of our room and used them.
About the noise--Our first day there, we went back to the room to catch a nap around 1pm, and I kept hearing what sounded like a fog horn every 10 minutes. This is with the balcony door and blinds shut. Turns out it was just the boat taxis docking at the Boardwalk dock. Took a while to get used to, but then it just becomes part of the special Boardwalk ambience.
From time to time a live band playing old ragtime (or something like that) songs will stroll down the Boardwalk during the day and in the evening, and you will get to sit out on your balcony and enjoy the free show. To me that was one of the biggest treats.
At night, the boats are no longer running so you don't hear the horns, and really, it is generally pretty quiet. The ESPN bar at the end of the Boardwalk plays their trademark music all day, and that would be about the only thing that could get old. Besides the crowd noise, it really wasn't too bad. After about midnight, it is completely dead, and all the shops are closed. But let's be honest--if you are staying in a room with a Boardwalk view, you better be ready for SOME noise. History will show that Boardwalks ARE kinda noisy by nature, and to me that was one of the coolest parts of staying there. You get a constant, carnival-like atmosphere, one that the garden view guests miss out on. But its all in what you like.
Hope that helps.
By the way, I swear on the concierge floor they pipe in some type of sweet, woody smell that is not in the rest of the resort. AWESOME!!