If you want to attribute it to a single person I would have to think that Rex Chapman would be the one responsible for many good picks.
I have heard people giving Rex props for scouting before - of course, it might have been you on here in times past - but I've never heard any specifics.
As far as Percudani is concerned I've heard him mentioned as being responsible for Marjele, Nash, Finley, Marion, Person and Ceballos - that I recall off the top of my head.
Recently read an old article from 1994 (I think) detailing how Percudani held out for Marjele when nobody else wanted him. You might recall the team was jeered, booed (and I could even say barracked) when that pick was announced.
Here's a quote from Wikipedia about Chapman:
Chapman would play 53 games during the 1999–2000 season, but he became re-injured and decided to retire from the NBA then.
...
After retiring from active play Chapman remained with the Suns, first as a scout and later as Director of Basketball Operations
It appears he overlapped with Percudani for 00-01 season and then stayed on so he may well have responsible for Amare and Barbosa, but then he gets credit for Casey J. and Zarko C., too - Casey, because of who was passed on to get him, stands out as a particularly horrible pick. Zarko was unfortunate but he looked frail as all get out and that might have determined why his injury shut him down as far as the NBA is concerned.
Imagine if we'd chosen Tayshun Prince instead of Casey - and he was the choice of the people on here who followed the college game. Carlos Boozer was still available too but heck, half the league passed on him after we chose CJ. Personally, I wanted Gadzurich but I have to plead extenuating circumstances as I don't know jack about college ball.