I stayed in the Garden wings with my children in May of 02, I faxed room request and asked for a room closest to the tower/main building on a lower floor, they gave me the first room on the first floor which was very convenient HOWEVER, it was a handicapped room and their bathrooms are different, there is no separate potty (I have boys and girls and they needed that) also it was VERY noisy. I requested to be changed the next day after a night of no sleep and they were very happy to do so. I got a room in the South Tower facing the monorail (which was pretty cool for the kids) on the third floor near the elevator, this worked out excellent.
So, my advice is, if you are looking to stay close to the Tower expect noise, but definitely go to the upper floors this will cut down on the noise level.