Despite NFL scouts and analysts spending months determining the best players in the upcoming draft, there's no guarantee that the top pick will go on to be great.There have been way too many instances of the number one overall pick not working out, such as JaMarcus Russell or David Carr.While the players selected with the top pick don't always work out, there have been times where teams have hit home run picks, taking players who changed the face of the franchise for a generation.NFL Draft best number one picks#5 - Troy AikmanTroy Aikman with Ezekiel ElliottThe Dallas Cowboys took QB Troy Aikman out of UCLA with the first overall pick back in 1989. He would go on to to be one of the most successful players of the 1990s, winning three Super Bowl rings and a Super Bowl MVP.Aikman was voted to six Pro Bowls during his career, passing for 32,942 yards and 165 touchdowns. He was inducted into the Pro Football Hall of Fame in 2006.#4 - Terry BradshawTerry Bradshaw at the NASCAR Cup Series O'Reilly Auto Parts 500Taken first overall by the Steelers back in 1970, Terry Bradshaw became the first QB to win four Super Bowls, and was one of the best in his position during his career.Bradshaw was an excellent game manager and had multiple 300-yard passing games in those Super Bowl victories. He was a first-ballot Hall of Fame inductee in 1989.