While engine performance can shorten the amount of runway a 747 needs, it is still restricted by its highly swept wings (37.5°) which is optimized for high cruising speed. The 747 is still the fastest subsonic airliner that has ever existed. The 747 Advanced will cruise at Mach .86 which is faster than the 400 model's and A380's Mach .85. The A380 due to advances in aerodynamics (a supercritical wing) is able to cruise at the same speed as the current generation of 747's while have less wing sweep which gives it better takeoff performance.
Minor nit: The Convair 880 and 990 were faster than the 747, I'm pretty sure. I think the 880 could cruise at Mach .87, or higher if they felt like really slurping down the fuel. Those old GE turbojets weren't exactly efficient.
}:-)4