Interesting topic. Alright, let's look at the criteria Mr. Jurgela has:
1. Early superstar of the sport.
I think Honus Wagner would be known to baseball fans even if he didn't have his famous T206 card. The same isn't true for Meredith. I would say that 99.99 percent of soccer fans don't even know who he was. I didn't learn who he was until I got deep into soccer card collecting.
Fair enough. Try asking a non collecting baseball fan who Honus Wagner was and see what you get. Most of my non collecting friends have no idea. And those that do see to think he played for the Dodgers or the Yankees! 
2. Highly collected set.
First you wrote "highly collected set," and then you proceeded by saying "for those of you who don't know this set."
Funny. If this is a highly collected set, then you shouldn't have to explain it to us. Oh, and I have never heard of this Taddy set either.
Highly collected in UK, not USA. Pretty sure that if you said T206 to a Brit, they would have no idea what you are talking about. Just a guess.
And finally, it looks to me as if you selected Meredith because he played in the same era as Wagner, but it doesn't have to be this way.
I actually considered a bunch of cards and can make some other proposals, but was hoping to get others' perspectives first
My selection is this card below:
1957 Balas Futebol #11 Pele
This is the first card of the king. I am not sure how many examples exist, but it's extremely difficult to locate (so don't even try searching for it on eBay
) The above picture was taken from an album owned by the biggest soccer card collector in Brazil, Moacir Peres, a retired judge.
I would give up my whole entire soccer collection for this one card.