When Tyson Alualu was drafted at 10th overall in the 2010 Draft anybody and everybody with a voice shouted from the rooftops that it was a reach. Mel Kiper gave the Jaguars a D in his draft grades, the lowest grade of 2010, because the Jaguars reached by half of a round to take Alualu. Chris Steuber of Scout.com called the pick an "obvious panic move."
A year later he hasn't proven to be the best player out of the 2010 Draft, but most would argue that he lived up to the expectations of a rookie drafted in the top 10. For some that proved that Alualu wasn't a reach and that he was a good decision by Gene Smith. For others, including Kiper, he is and will always be a reach even if he turns out to be a Hall of Famer.
Kiper argued that even if Alualu has a Hall of Fame career, the Jaguars still didn't need to take him at the 10th pick and cost themselves value by doing so. To sum up his argument, even if you know a player that will be drafted in the 7th round is better every player in the 2nd round and in between, you don't draft him in the 2nd round. You take the player as low as you can and maximize the value of your picks.
Unfortunately for Kiper there are some serious flaws in his logic. So much so that I don't believe there is any such thing as a reach or a steal, at least there isn't until the players see the field.