On these sorts of lists and criteria, and having had the privilege to meet a number of these amazing pilots, I'd put it neck and neck between Eric Brown and Neil Armstrong.
Not just on their pure flying achievements, but because both put huge amounts into promoting the whole breadth of the science and pursuit of aeronautics, and both have been possessed of huge humility and willingness to support others.
There are others who have done great things with flying machines, many who have pushed the bounds of aeronautics in one way or another, and a few who even show humility. But, I can think of no others who reach supreme heights in all three in the way that these two have.
Actually maybe one, not too far behind them - which would be George Cooper, who is held in similar regard within the flight test profession to Eric Brown, but is probably much less well known outside it.
http://history.arc.nasa.gov/hist_pdf...o_20120724.pdf
(CG, at 98, is 3 years older than EB - I happened to meet him three months ago and he's still doing well, if not quite as fit as EB.)
G