I witnessed what became something of a landmark incident at Gatwick in the early 1990s when an Air New Zealand 744 went around whilst in the flare, touching the runway in the process.
A storm had just gone through, leaving the runway wet and a slight tailwind for the runway in use (26L), as is often the case after the passage of a storm cell.
Whilst the aircraft appeared to be making a normal approach, there was considerable 'float' and the a/c hadn't touched the surface for some distance past the aiming point. I was in a vehicle on the Northern Runway (08L/26R) approximately abeam the aiming point. The engine note increased and the a/c pitched up. However, due to inertia, the a/c continued to sink slightly, the mains briefly touching the surface and running along for a couple of hundred metres before becoming airborne and climbing away. We never saw the a/c again, as it diverted to Heathrow, I guess not having sufficient fuel for another go with reserves.
The go-around seemed like a good call, with the tailwind and float and there had recently been a couple of over-run incidents elsewhere in the world.
This incident is still mentioned especially in ATC training at Gatwick illustrating the go-around decision-making process and that controllers can see an a/c touching during this manoeuvre.
I also use it as an illustration and practical now that I'm teaching other people how to safely approach and go-around in all configurations.
Cheers,
TheOddOne