This is a post I have used for Bleacher Report and a school project. It is one of my favorite writings, so I've decided to use it as my opening blog post.


Introduction
Dwight Freeney.  Julius Peppers.  Michael Strahan.  These are some of the greatest pass rushers of the last 20 years.
All these names are synonymous with defense, and not just any defense, but a 4-3 defense.

Overview
If you are unsure of what the differences are between different styles of defenses, or if you have no clue about the styles, here is a rundown.
The major differences between a 4-3 and a 3-4 is how many people are on the line of scrimmage. The most general, basic 4-3s have four linemen with one or both of their hands in the ground.
This is where the four from the 4-3 comes in. The three is how many linebackers are behind them, standing up on both feet.
The 3-4 is, as you can imagine, the opposite. There are three linemen on the ground, with four linebackers behind them. But not all linemen are created equal.
In a 4-3 most of the time the linemen's duty is to get up field and wreak havoc on the quarterback or a running back behind the line scrimmage.
In a 3-4, the linemen's job, plainly and simply, is to take up space.
If you are reading this thinking, "Well where does the pass rush come from then?" then you are ahead of the game.
If you didn't think that, then you're just fine, too, because I'm about to explain it right now. In football, the pass rush usually comes from the edge, or around the offensive tackles.
That becomes part of the linebacker's job. The two outside linebackers come around the corner to make plays.

Facts
Now that you know the differences, it is time to decide what you would prefer. But before you make your decision, think about these facts:
Deacon Jones, who played in an era before sacks were kept track, claims he once had 26 in a season, which would be a still unbroken record today.
In fact, the reason that they are called "sacks" today is because of Deacon Jones.
He actually coined the term "sack" because when he did it, Jones wanted it to be like shoving the quarterback into a sack then beating over the sack with a baseball bat.
Yeah, he was rough.

Dick LeBeau
But that's not to say that the 3-4 doesn't have advantages. The 3-4 is becoming more and more popular today. The main reason for this, in my opinion, is Dick LeBeau.
LeBeau, in addition to being a Hall of Fame caliber cornerback ranking in the top ten of all time interceptions with 62 career picks, is also arguably a Hall of Fame coach.
He both created and installed the "zone blitz" into NFL history. The zone blitz is different from most blitzes because not of how many people are coming, but from where.
For example, LeBeau may send a corner to blitz, but have the 300+ pound nose tackle drop into shallow coverage. It messes up the protection schemes of the offensive line because there are still four people rushing, but from different angles.
Many NFL teams today, including The Buffalo Bills, Kansas City Chiefs, Houston Texans, Green Bay Packers and Washington Redskins have recently been implementing 3-4 packages, if not completely overhauling their defensive schemes to make the change to a 3-4.

Laurence Taylor
In addition to being popular with today's NFL, the 3-4 was a huge phenomenon because of a single player: Laurence Taylor. Taylor was a young, outside linebacker phenomenon for the New York Giants in the 1980's and early 90's.
He played with his hand up, on both feet in head coach Bill Parcells' 3-4 defense. Many consider him not only one of the greatest defenders in NFL history, but the most gameplanned for.
On every single play, before the snap, the quarterback had to say, "Where is number 56?" If not accounted for, Taylor would single-handedly change games, get quarterbacks benched, and offensive coaches fired.

Conclusion
I've done my part, now it's your turn. Which defense do you prefer? Let me know why in the comments. Either way, they both have the same goal, to not only stop opposing defenses, but to drive them backward.