You don't have to settle for mere idle speculation. Let me tell you how it came out on the three occasions when we did fight.
The first time was a year or two after SNOW CRASH came out. I was doing a reading/signing at White Dwarf Books in Vancouver. Gibson stopped by to say hello and extended his hand as if to shake. But I remembered something Bruce Sterling had told me. For, at the time, Sterling and I had formed a pact to fight Gibson. Gibson had been regrown in a vat from scraps of DNA after Sterling had crashed an LNG tanker into Gibson's Stealth pleasure barge in the Straits of Juan de Fuca. During the regeneration process, telescoping Carbonite stilettos had been incorporated into Gibson's arms. Remembering this in the nick of time, I grabbed the signing table and flipped it up between us. Of course the Carbonite stilettos pierced it as if it were cork board, but this spoiled his aim long enough for me to whip my wakizashi out from between my shoulder blades and swing at his head. He deflected the blow with a force blast that sprained my wrist. The falling table knocked over a space heater and set fire to the store. Everyone else fled. Gibson and I dueled among blazing stacks of books for a while. Slowly I gained the upper hand, for, on defense, his Praying Mantis style was no match for my Flying Cloud technique. But I lost him behind a cloud of smoke. Then I had to get out of the place. The streets were crowded with his black-suited minions and I had to turn into a swarm of locusts and fly back to Seattle.
The second time was a few years later when Gibson came through Seattle on his IDORU tour. Between doing some drive-by signings at local bookstores, he came and devastated my quarter of the city. I had been in a trance for seven days and seven nights and was unaware of these goings-on, but he came to me in a vision and taunted me, and left a message on my cellphone. That evening he was doing a reading at Kane Hall on the University of Washington campus. Swathed in black, I climbed to the top of the hall, mesmerized his snipers, sliced a hole in the roof using a plasma cutter, let myself into the catwalks above the stage, and then leapt down upon him from forty feet above. But I had forgotten that he had once studied in the same monastery as I, and knew all of my techniques. He rolled away at the last moment. I struck only the lectern, smashing it to kindling. Snatching up one jagged shard of oak I adopted the Mountain Tiger position just as you would expect. He pulled off his wireless mike and began to whirl it around his head. From there, the fight proceeded along predictable lines. As a stalemate developed we began to resort more and more to the use of pure energy, modulated by Red Lotus incantations of the third Sung group, which eventually to the collapse of the building's roof and the loss of eight hundred lives. But as they were only peasants, we did not care.
Our third fight occurred at the Peace Arch on the U.S./Canadian border between Seattle and Vancouver. Gibson wished to retire from that sort of lifestyle that required ceaseless training in the martial arts and sleeping outdoors under the rain. He only wished to sit in his garden brushing out novels on rice paper. But honor dictated that he must fight me for a third time first. Of course the Peace Arch did not remain standing for long. Before long my sword arm hung useless at my side. One of my psi blasts kicked up a large divot of earth and rubble, uncovering a silver metallic object, hitherto buried, that seemed to have been crafted by an industrial designer. It was a nitro-veridian device that had been buried there by Sterling. We were able to fly clear before it detonated. The blast caused a seismic rupture that split off a sizable part of Canada and created what we now know as Vancouver Island. This was the last fight between me and Gibson. For both of us, by studying certain ancient prophecies, had independently arrived at the same conclusion, namely that Sterling's professed interest in industrial design was a mere cover for work in superweapons. Gibson and I formed a pact to fight Sterling. So far we have made little headway in seeking out his lair of brushed steel and white LEDs, because I had a dentist appointment and Gibson had to attend a writers' conference, but keep an eye on Slashdot for any further developments."