The Goat of all Goats?

It depends how you define the question.

If it is "American Sports", I don't think there is a contest.

If it is "A Major American Professional Sports League" then he is in the conversation and its a matter of opinion.

For myself: Jim Brown is the greatest football player I've ever seen play, Koufax is the greatest pitcher I've ever seen pitch, Mays is the greatest baseball player I've ever seen play, Art Monk is greatest high school athlete I've ever seen, and Ray Rice is the best high school football player I've ever seen. (I only saw Monk run track.)

As for Basketball, Jordan, Magic, Russell

It’s Gretzky.
The rules were changed and the goal was moved because of him. QED.

I think comparing players across different sports in different eras is like apples and oranges. There's no objective measure over the relative variables. And, it depends how one defines "greatness." Let's say, in this case, "greatness" is defined by most "accomplished." Brady is the most accomplished NFLer. Also, players shouldn't be handicapped by the cultural context of their times, rather it's an asterisk in the mind, but that's no scientific way to reject their performances relative to their immediate contexts, as that's all they could and did have to play in. Comparisons cross-era are very difficult, but we know what they did in their own times relative to the rest of their generation.

So, I would put Brady at the top in football, Ruth at the top in baseball, Jordan at the top in basketball, Gretsky in hockey. It's fairly simple, we know the best of all times. Even if you could choose across sports and eras, who can pick among Brady, Ruth, Jordan, Gretsky? They all did the best anyone could in their sports -- impossible to pick one. Now, recency bias comes into play here, we're so far away from Ruth, even Gretsky and Jordan. Let's respect the verifiable history.

And, I agree with the Druid that Brady really put to rest the idea that Belichick had more to do with NE's success. No way. Tip of the hat to the awesome Brady, we'll never see anything like this.

I've seen the "most accomplished" argument used re: Brady a fair bit this week - and IMHO, it is apt because to me he's not the GOAT even of the NFLers - Brown is. But "Most Accomplished" - I'd buy that.

However, if your are going to go for "most accomplished" - nobody was more accomplished in his sport than Bill Russell.

(and re: Belichik - keep in mind little Bill still has more Super Bowl rings than Brady)

Ah, another point-- it's very hard to compare across different positions even in a given sport, especially football. And there's the issue of peak performance over longevity -- Jim Brown was a force of nature in his 9 seasons, absolutely. But how do we compare a running back to a quarterback? Then, Brown as an RB was more integral to his team than a QB. Now, it is different. And what about the titles? Brady's 7 tops all. He seems to lift his teammates, bring in the guys to a team like he did this year, and his admirably singular focus to win is unmatched. As for Belichik rings, I don't equate assistant coaches' rings to that of a starting QB. I'm not a Brady lover or hater -- I'm a Steelers fan and always loathed NE and Brady -- just calling the shots objectively.

Another thing about Brown. He makes Shoeless Joe and Pete Rose look like choir boys and is very competitive with OJ Simpson and Mike Tyson regarding arrest history. Wonder if he played baseball for 9 years in the 2000's and was as good at baseball as he was at football, I seriously question if he would get voted into the HOF given his lengthy history of arrests for assault etc., particularly against women? Not the most savory of characters and very much the antithesis of Brady as a positive role model.

One thing is pretty much inarguable (I think): Brady's 4 championships after he turned 37 is unmatched.

Did some research this morning. Watched a bunch of films of Jim Brown. Amazing blocking and great receiver as well as the best back ever. But then I found this 2010 ranking by a "blue-ribbon" panel assembled by the NFL Network. The members of the panel were current and former NFL coaches, players, executives, and members of the media." They ranked the top 100 Football Players of all time. #1 was Jerry Rice, Brown was #2 and Lawrence Taylor #3. Very validating for me for those were the three guys I listed as the best NFL players ever, (after Brady) although I certainly didn't have them in order.

One thing shocked me. Bart Starr looked like a high school quarterback compared to Brady or Mahomes. And Cleveland had a great supporting cast during the one championship during the Brown era, in 1964. Paul Warfield, Leroy Kelly and Gary Collins, for example on offense. Two great receivers and an backfield of Kelly and Brown. Also Dr. Ryan, later a math professor at Rice and Yale had his one great season as quarterback of the Browns that year.

Brown had 3 MVP's in his 9 years with the Browns. But only that one championship. The Browns had also won two NFL championships in the two years preceding Brown's rookie year. They then made it to the championship game in his first two years in the league, but lost both times. Clearly the Browns of the mid 1950's were a great team even without Jim Brown.

Given the solid supporting casts that Brown worked with, Brady's 7 rings and 10 Superbowl appearances, is looking better and better. And maybe the NFL knew what they were talking about when they determined that Jerry Rice was the greatest of all time, at least in 2010 when they compiled that list.

The Winningest Athletes of All Time Sports

Bill Russell: 2 college championships with the University of San Fran (which included a 55-game win streak at one point), an Olympic gold medal, and 11 NBA championships in 13 years. Just insane.
Michael Phelps: 28 Olympic medals including 23 golds make Phelps the most decorated Olympian of all time.
Rocky Marciano: Only heavyweight to retire undefeated at 49-0. Not bad for a white guy from Brockton, MA.
Jack Nicklaus: 18 majors including 4 US Open wins, and 6 green jackets. with 73 PGA Tour wins overall.
Tiger Woods: 15 majors, and tied for the most PGA tour wins of all time with 110.
Yogi Berra: 10 World Series rings as a player and another 3 as a coach.
Henri Richard: Nicknamed “The Pocket-Rocket,” Richard won 11 Stanley Cups with the Montreal Canadiens in his 20-year NHL career.
Joe DiMaggio: 9-time World Series champion and 1 Marylin Monroe.
Kareem Abdul-Jabbar: 6-time NBA champion, 3-time college champ with UCLA (over which they went 88-2), and captain of a Power Memorial High School basketball team that won 71 straight games and 3 New York City Catholic championships.
Roger Federer: 20 Grand Slams and 103 career titles.
Pele: Only soccer player to be a part of 3 World Cup-winning teams. Pele also led his original club team, Santos, to 10 championships in the Campeonato Paulinista league. And let us not forget his 1977 North American Soccer League championship with the New York Cosmos.
Michael Jordan: 6 championships in 8 years, 2 gold medals, and 1 NCAA championship with the Tarheels.
Tom Brady: 6 Super Bowls, 3 league MVPs, 16 division titles and a quarterback high 245 regular + postseason victories.
Serena Williams: Winner of 23 major singles titles, most of any man or woman in the Open Era.
Pete Sampras: 64 career titles including 14 Slams.
Alexander Karelin: Though most remembered here in America for his stunning defeat at the hands of Rulon Gardner, “Alexander The Great” went undefeated in international Greco-Roman wrestling competition for thirteen years, the last six of which he didn’t even give up a single point.
Otto Graham: Took the Cleveland Browns to the championship game in every one of the ten years he played, winning seven and going 105-17-4 over that span. He also won a championship playing professional hoops with the Rochester Royals.
Martina Navratilova: 167 singles and 177 doubles career titles (both records for men or women) Her singles career includes 9 Wimbledons and 4 US Opens.
Lance Armstrong: He might be doper, but he’s the winningest doper there ever was.
Mickey Mantle: 7 World Series rings in 12 years and a 1956 Triple Crown.
Larissa Latynina: The Soviet gymnast has held the all-time Olympic medal record for nearly a half century with 18, including nine golds.
Carl Lewis: 9 Olympic golds and 8 world championship golds. Side note: Lewis was drafted by both the NBA and NFL, though never played a game for either.
Kelly Slater: The most decorated surfer of all time has won a record 11 ASP World Championships, his titles spanning an incredible eighteen years from age 20 to 38.
Edwin Moses: Won an astounding 122 consecutive races (107 finals), 2 Olympic golds, and 2 World Championship golds.
Robert Horry: 7-time NBA champion with 3 different teams.
John Havlicek: 8-time NBA champion and a NCAA title.
Cael Sanderson: Wrested to an incredible record of 159-0 with 4 consecutive NCAA titles for Iowa St before capturing gold in Athens 2004.
Bill Dickey: 8-time World Series Champ.
Magic Johnson: 5-time NBA champion, 1 gold medal, and enough money to makes AIDS his bitch.
Bart Starr: 5-time NFL champion (including the first 2 Super Bowls)
Joe Montana: 4-time Super Bowl champion and an NCAA national title at Notre Dame.
Lou Gehrig: 6-time World Series champion and the luckiest man on the face of the Earth.
Kobe Bryant: 5-NBA championships (one more than Shaq) and 2 gold medals.
Shaquille O’Neal: 4-time NBA champion, 6 crappy albums and 11 crappy movies (see: Kazaam) And he beat up Golden Boy Oscar De La Hoya.
Babe Ruth: 7 World Series trophies with both the Sox and Yankees.

Good topic.

I will go with Ruth.

I can't consider Jordan because of Wilt, who was statistically better.

Jordan's best scoring season he averaged 37.1, Chamberlain had 4 season's better then that, including a 50.4.
Jordan's best single season field goal percentage was .539. Chamberlain's career was .540.
Chamberlain averaged 22.9 rebounds per game, Jordan averaged 6.2.
Jordan did average more assists, 5.3 to 4.4.
Jordan also won more championships 6 to 2.
Jordan did play professional baseball. Chamberlain is in the Volleyball Hall of Fame, though I believe thats more to do with his impact on the game then his talent. Reportedly he was the most feared 'hitter' in volleyball but was weak in most other areas.