Not so long ago, most MLB lineups were constructed the same way. Speedy hitters would lead off the game, getting on base and into scoring position for the big power bats in the three and four spots to drive them in. A few more low-average, high-power guys would follow, and then some glove-first players would comprise the last spot or two, except in the National League, where the pitcher would always bat last.
Nowadays, lineup construction is less rigid. Hitters with high OBPs are found batting leadoff, even if they aren't fast. Some of the biggest home run threats in the game are batting second. Pitchers are batting eighth. No longer are there strict guidelines that lineups have to adhere to -- teams are free and willing to construct their lineups in whichever way they think will help their team most.
With that said, it's more interesting than ever to compare the players who occupy the same position in the lineup. Because they could have vast differences in their playing styles, it certainly makes it more difficult to compare, as well as more contentious. Below, I give it my best shot, selecting the hitter from each league who I think is the best at his spot in the lineup.