Ok this graph is making me really excited!
Normal glass reflects about 4% of normal incident light,
multi coated glass reduces that that to about 0.4% (if the graph is based on SMC then pentax was doing very well at 0.3%)
HD has got this down to 0.1% or less.
Think of it as SMC being 33% better than the competition and HD being 300% better than SMC and all of a sudden it sounds fantastic, especially when you multiply the effects over multiple elements.
Not only does it affect lens flare but critically it has a major effect on contrast as well, which hasn't really been mentioned but is one of the most critical performance criteria of a good lens IMO.
The only advantage of Aerobright and other nano coatings is that it may be able to deal with low angle incident light better, or you could just put your lens hood on!