Just disembarked from United 397 from Atlanta to Chicago and I=B9d like to send a note of appreciation and gratitude to those in the industry who strive to attain the highest levels of human performance. (and an appreciation for Channel 9) ... And I wish I had a camera. Inbound to 4R was a little congested for the 6pm arrival bank, and the mix of regular jets and RJs were giving controllers their share of joy. Our flight was given direction to S-curve on the approach (fun in itself!), but at a few hundred feet of altitude left a Comair RJ wasn=B9t hustling off the runway; we went around. Of course going around at O=B9Hare is not like a go-around at Hartsfield, and this is where it counts. There was a United A320 at 500=B9 into 9R which if they went around would of REALLY created some fun. But more importantly there was an American MD80 departing on 9L AND there was another jet rolling for departure on 4L. The tower controller, without a flinch in her voice, requested an immediate sharp left turn and requested an immediate confirmation of the visual sighting of the American MD80 now in the air off of 9L. Our pilot, of course aware of the standard go-around path, acknowledged with no wavering in his voice the instructions. The tower controller directed a new heading of 320 and an expedited ascent. Once again, no wavering of voices, as if this was a regular day occurrence we departed O=B9Hare as fast as we approached it. And so in something you=B9d only expect to do in Flight Simulator we roared over the terminal buildings of O=B9Hare at a scant few hundred feet, 30 degrees of bank and engines of our =B3pocket rocket=B2 A319 screaming at near full throttle. I=B9ve been through O=B9Hare nearly weekly for 4 years, but I=B9ve never seen it the way I did today. I wish I had a camera, and am grateful for the extensive training that occurs. When it counts, it works. Matthew