My initial reaction was golf. Golf results tend to be a little more random, which means that you get a decent number of no-name or journeyman players who win one major, but that number drops dramatically at 2+. You generally have to be a pretty good player to win 2+ majors.

Tennis, however, is a bit more consistent, and you don't get tons of 1x champions, and those who are 1x champions are usually pretty good players who get a favorable draw (i.e. good matchups late) or just play really well over the 2 weeks.

I do think the one caveat for tennis is the different surfaces. showing prowess on different surfaces is pretty important in tennis history, and so a player who takes 2 major titles on different surfaces (e.g., Halep on grass and clay, or Hewitt on hard court and grass) really sets himself apart from not only the 1x players but also the players who win 2-3 titles on one surface.

One point that cuts against golf is that a decent player has a much longer career on tour, and so gets many more chances to win 2 majors. Jim Furyk is a good example. He won the US Open and has had 15 years worth of quite a few good chances to capture that elusive 2nd major. in tennis he would have retired a year or two after his major win.

So I think my answer is as follows:

1. Tennis, if the 2nd major is on two different surfaces

2. Golf

3. Tennis, if the 2nd major is on the same surface

(http://www.autoadmit.com/thread.php?thread_id=4305042&forum_id=2#38548534)

even putting aside the historically unprecedented big2+lance era where very few guys win a single slam, there are way fewer guys who ever win a single tennis slam than win a single golf slam. so, winning 2x golf slams is a bigger deal and makes you stand out from the pack of scrubs.

winning one tennis slam plus an overall good career makes you a good HOF candidate. but tons of scrubs who have won one golf slam aren't anywhere close to HOF-worthy (is there even a golf HOF?).

and stfu about "surfath". nobody cares about shitmud, breh.

(http://www.autoadmit.com/thread.php?thread_id=4305042&forum_id=2#38548748)

I just did a count of guys who have won tennis majors in the Open Era -- there have been 54 men who have won a tennis major in the Open Era (or open era + amateur era). 25 men have won a single major, while 29 have won 2+ and 21 have won 3+. So it does actually seem like 2+ gets you into a much rarer club. and that's without talking about surface differences.

Let's take a look at PGA tour players who have won exactly 2 majors since 1968 (when tennis' open era started):

Tony Jacklin

Dave Stockton

Johnny Miller

Hubert Green

Andy North

David Graham

Fuzzy Zoeller

Ben Crenshaw

Sandy Lyle

Bernhard Langer

Greg Norman

Curtis Strange

John Daly

Lee Janzen

José María Olazábal

Mark O'Meara

Retief Goosen

Ángel Cabrera

Zach Johnson

Martin Kaymer

Bubba Watson

There are a fair amount of guys on that list who aren't great players, and while sure the list of guys with only 1 major includes a lot of weak players, it also includes a lot of really strong players -- certainly as strong as players on this list -- especially because (as we always discuss) regular PGA tour wins are more important than ATP tour wins. Guys like Tom Kite, David Duval, Davis Love III, Corey Pavin, Fred Couples, Tom Weiskopf, Craig Stadler, Paul Azinger, Jim Furyk, Jason Day, Sergio Garcia, etc. are all similar quality to most of the 2 major guys.

So again, I'm not sure that the 2nd major is getting most of those guys a lot more cred than the 1 major guys, especially given overall tour play.

(http://www.autoadmit.com/thread.php?thread_id=4305042&forum_id=2#38548859)