If you forget about Peyton Manning, Matt Flynn, Tim Tebow and the rest of the quarterback drama that's taken place this spring, perhaps the biggest roster-movement story this offseason took place in Buffalo.

The Bills gave former No. 1 overall selection Mario Williams an enormous deal (six years, $96 million) to try and improve one of the NFL's worst pass rushes. 

As the NFL transitions more and more to the passing game (teams regularly dropping back 40-50 times per game) defensive ends have come to command that type of money these days. 

Of course rushing the passer is a defensive end's only area of responsibility, but it is their most important. And a great defensive end can either sack the quarterback, force a fumble or cause the passer to unload a bad throw resulting in an interception, each a potentially game-changing moment. 

The 10 men on this list all excelled at their position.

No. 10: Julius Peppers

Career: 2002-present

Teams: Carolina Panthers, Chicago Bears 

Achievements: seven-time Pro Bowler, five-time All-Pro

One of the two active players on this list, Peppers has not exactly been the most consistent defensive end of all time: He's had some down years and lean stretches. 

But at times—first as a Panther and even recently as a Chicago Bear—where he's been the most athletic, most gifted, most dominant player on the field. 

He is so quick off the snap that he can give any offensive tackle fits, in both the running and passing game.

If Peppers is healthy, at any point in the game, he's capable of a sack-strip-fumble or—much more of a rarity—picking off a pass and running it back on his own: He's returned two of his eight career interceptions for scores. 

No. 9: Jared Allen

Career: 2004-present

Teams: Kansas City Chiefs, Minnesota Vikings

Achievements: four-time Pro Bowler, four-time All-Pro

Allen didn't come out of college with nearly the same type of fanfare and hype as Julius Peppers, who was touted as the next Lawrence Taylor coming out of UNC. 

But since joining the NFL he's grabbed sacks in bunches and has been worth every penny of that $72 million deal the Vikings gave him. 

Twice he's led the NFL in sacks (including this year, when he nearly surpassed Michael Strahan's single-season record) and is much better against the run than people realize. 

But arguably his greatest strength? Consistency.

Not only does he rarely go more than two starts without landing a sack, but he's only missed two games since his rookie season. 

No. 8: Lee Roy Selmon

Career: 1976-84

Teams: Tampa Bay Buccaneers

Achievements: six-time Pro Bowler, three-time All-Pro

The first draft choice of the Buccaneers, Selmon proved a tremendous investment.

Sure, Tampa Bay didn't win a Super Bowl title—although they came close—but Selmon did land in Canton as a Hall of Famer. 

He used his quickness and strength to harass quarterbacks and transform the once-embarrassing expansion organization that lost their first 26 games into a perennial playoff team.

Take 1979, for example. That season—coincidentally when Selmon won the NFL Defensive Player of the Year award—the Buccaneers defense allowed the fewest points and yards in the league and reached the NFC Championship Game. That's an impact player. 

No. 7: Gino Marchetti

Career: 1952-66

Teams: Dallas Texans, Baltimore Colts

Achievements: 11-time Pro Bowler, nine-time All-Pro, two NFL championships

Because Marchetti played a quarter-century before the sack was officially a stat he's not going to appear in the record books. More to the point since he played in an era when the passing game wasn't used nearly as often—remember, the only prolific passer in the NFL during Marchetti's era (John Unitas) was on his team—he didn't have many opportunities to rush the  quarterback.

That Colts dynasty was obviously powered by its great offense (Unitas, Lenny Moore, Alan Ameche, Raymond Berry, Jimmy Orr, Jim Parker) but Marchetti was the centerpiece of that defense, a unit that was repeatedly among the top rated in the NFL. 

No. 6: Howie Long

Career: 1981-93

Teams: Los Angeles/Oakland Raiders

Achievements: eight-time Pro Bowler, three-time All-Pro, one Super Bowl championship

As a rookie, Long joined a defense loaded with talent: The Raiders already had Ted Hendricks, Matt Millen, Lester Hayes, Super Bowl XV hero Rod Marin and would soon add Hall of Fame cornerback Mike Haynes. 

But by the end of his career, it was Long who was the superstar and leader bound for Canton. 

Although he didn't necessarily rush the passer with the same type of ferocity or consistency as some of his contemporaries, Long became one of the most complete defensive lineman in the game. In defending the run, Long was rarely out of place or unable to make the play on the edge. 

No. 5: Chris Doleman

Career: 1985-99

Teams: Minnesota Vikings, Atlanta Falcons, San Francisco 49ers

Achievements: eight-time Pro Bowler, three-time All-Pro

On some level, I can understand why Doleman was repeatedly passed over for a spot in the Pro Football Hall of Fame: He wasn't "the greatest" defensive end of his era. In fact, he wasn't even the second greatest defensive end of his era.

But that's just a case of bad timing: Doleman was an incredible pass-rusher who dominated the game and—aside from one injury-plagued season with Atlanta—didn't miss a single start between 1987 and 1998. 

He remains fourth on the all-time sack list, but just as (if not more) important than his knack for bringing down quarterbacks was his ability to create turnovers: He forced 44 fumbles (and recovered 24) during his career. 

No. 4: Doug Atkins

Career: 1953-69

Teams: Cleveland Browns, Chicago Bears, New Orleans Saints

Achievements: eight-time Pro Bowler, four-time All-Pro, two NFL championships

As great as Gino Marchetti was, Doug Atkins was the greatest defensive end of that era: and not just because Atkins' Bears actually had to face Johnny Unitas' Colts twice per season.  

With his incredibly enormous 6'8"-frame (especially unusual in his time) Atkins harassed opposing passers, making it difficult to even unleash a pass, let alone complete one. 

And when the great George Halas—who didn't always see eye-to-eye with No. 81—says “there never was a better defensive end” than Atkins, there isn't much else to be said. 

No. 3: Bruce Smith

Career: 1985-2003

Teams: Buffalo Bills, Washington Redskins

Achievements: 11-time Pro Bowler, nine-time All-Pro

Ultimately, Smith's greatest legacy was rushing the passer: He retired with more sacks (200) than anyone in history, a record he still holds to this very day. 

But Smith was one of the most complete defensive lineman ever to play the game.

During the early years of his career, he was largely a one-dimensional, pass-rush-only defensive end.

But beginning in 1990—the season that he won the NFL's Defensive Player of the Year award—he started becoming much more involved in defending the run and it helped Buffalo build the AFC's top defense. 

And although he was best recognized for what he achieved as a member of the Bills, don't discount his (relatively brief) career in Washington. Between 2000 and 2002—already in his late 30s—Smith only missed two starts and recorded 24 sacks in 36 games.  

No. 2: Deacon Jones

Career: 1961-74

Teams: Los Angeles Rams, San Diego Chargers, Washington Redskins

Achievements: eight-time Pro Bowler, five-time All-Pro

Take the numbers (and the source) with a grain of salt, but according to Jones he recorded unbelievable sack totals during the peak of his career. 

The sack wasn't an official stat in Jones' days but to hear him tell it, he recorded 20 sacks in 1963, 26 sacks in 1967 and 24 sacks in 1968, each during a 14-game season. 

But regardless of the validity of those numbers, Jones contributions to the game were immeasurable.

For one, he invented the term "sack"....with especially colorful language: "You take all the offensive linemen and put them in a burlap bag, and then you take a baseball bat and beat on the bag," Jones told the LA Times in 2009, explaining the word he coined. "You're sacking them, you're bagging them. And that's what you're doing with a quarterback."

But on the field, he was the enforcer, the mouth piece and the top pass-rusher on arguably the greatest defensive line in NFL history, the Fearsome Foursome. 

No. 1: Reggie White

Career: 1985-2000

Teams: Philadelphia Eagles, Green Bay Packers, Carolina Panthers

Achievements: 13-time Pro Bowler, 10-time All-Pro, one Super Bowl championship

White's pass-rushing skills and sack totals peaked while he was in Philadelphia. There he led the NFL in sacks in back-to-back seasons (he recorded 39 in just 28 games between 1987 and 1988) and mentored Clyde Simmons and Jerome Brown to the point that they too became All-Pro defensive lineman. 

But—rightfully so—White is best remembered for his time in Green Bay.

After signing his free-agent deal in 1993—one of the most important and memorable moves in NFL history—he instantly made the Packers defense into a champion-caliber one.

And although you could point to his sack totals (198, second most in NFL history), the pair of NFL Defensive Player of the Year awards he won or his rank on the NFL's Top 100 list (seventh overall, highest for a defensive lineman) the best example of White's dominance came in Super Bowl XXXI.

That night in New Orleans, when the Packers won their first Super Bowl title in 29 years, White (and his powerful right arm) absolutely abused Patriots offensive tackle Max Lane. Watch clips from that game and try to name a better defensive end. Ever.