Top 3rd overall picks: Carmelo Anthony (2003), Pau Gasol (2001), Deron Williams (2005)
Bottom 3rd overall picks: Adam Morrison (2006), Darius Miles (2000), James Harden (2009)
In the last few years, there have been a number of drafts where the 1st and 2nd overall picks are the two top prospects, and then there's "everyone else." 1999, 2004, 2007, 2008, and even 2010 were like that. And in most of those years, the team with the #1 pick got it right, and the #2 got it wrong.
But after that's all said and done, the #3 pick is usually a toss up. It usually fills a team need, or the team with the pick finds the next best available player. With a lot of prospects to choose from after the hype of 1 and 2, the choice is usually carefully selected, ensuring the best available option. Those options have included Carmelo Anthony, Baron Davis, Pau Gasol, Ben Gordon, Al Horford, OJ Mayo, and Deron Williams.
Even though James Harden is in the bottom 3, he's still got the potential to prove people wrong after one year of playing.
2010 3rd overall pick: Derrick Favors, New Jersey Nets