For ATL the perfect point guard prob would have to be either TJ Ford or someone like Early Boykins. They would have been easier to acquire, but idealy Allen Iverson would really help. He would take so much of the defense's attention and also give them a definate scorer at crunch time.
At center, the Hawks could really use and athletic shotblocker/rebounder. Some guys that fit the bill are Nene, Marcus Camby, Dan Gadzuric, Sam Dalembert or Tyson Chandler...they can get out and run