Phil,
It's hard to believe that the E95 Wagner doesn't cost more than it does, but since its the last card in the set that I still need, I'm going to say it needs to be much cheaper until I can get one...then it can rise to the stratosphere all it wants.
My real vote though goes to Eddie Plank. It is simply a gorgeous card, with the same iconic image as his T206 rarity (even better actually) and can be had at the same price as a Andrew Luck autographed rookie card.
That seems criminal to me.
An earlier post mentioned Lajoie, but he's not technically in the set (E95) that you first mentioned, despite many considering the E96 as a second series.
That card is a beauty too, and Nap's mainstream cards are pretty acheivable and somewhat undervalued. I've included scans of my armpit versions
