The 5th printing of the 1st edition of the first RPG product.
First, let's go back a step. In my view, the original edition of Dungeons & Dragons is the best RPG product ever, both in terms of content and physical production. I know that might earn a sneer from some-especially regarding the physical production. The booklets were printed entirely in black and white with the minor exception of the red, green and blue titles. The interior font was primitive and much of the art was amateurish (or so it has been claimed).
But I like the look of it. I prefer the simple, clear and non-distracting font and layout. The tasteful line drawings of characters and monsters stimulate the imagination as opposed to mimicking a screenshot from the latest video game. Interestingly, in the three original edition booklets, despite the important place combat plays in the game, there is only one obvious illustration of an actual combat scene (it's a drawing of a Lycanthrope about to hurl someone to his doom). Contrast this with the myriad full color spreads of battle in, say, any of the 4th edition books, where each scene, with its desperate or angry facial expressions, poised weapons, jaws, claws and so on, appears to be capturing THE MOST EXCITING POSSIBLE MOMENT, again as if trying to qualify for a best screenshot contest. Here are two examples:
Wait, haven't I seen those two somewhere before…
It's so EXCITING!!!!!!!!!!!!!!!
Now, I know that many would prefer the modern style. Indeed, almost by definition it would seem that the majority of current RPG purchasers prefer it. I don't. But enough said about that.
To return to the original edition, in actuality there aren't that many differences in content or production between the seven plus printings from 1974 to 1979. The excellent Acaeum breaks down what differences there are. The first three printings featured a wood colored box with a picture of a mounted warrior on a rearing horse (also originally present on the cover of Men & Magic). This was replaced in the 4th printing with a white box featuring a Wizard firing a wand at a group of goblins (or could he indeed be striking with some kind of magic sword?).
Apparently, the first four printings used a relatively hard to read type setting. The 5th printing switched to a more friendly Helvetica font. The 6th printing kept the more readable font while excising or renaming for legal reasons most of the Tolkien elements-Hobbits, Ents, Balrogs and so on.
So I would go for the 5th printing-a readable font without the Tolkien excising-the version available, as far as I can gather, for most of 1976.
It sold for $10.00, or about $45.00 in inflation adjusted currency.
For that you got the box, three booklets, a stapled set of "Reference Sheets" and probably a one page set of errata. Curious and enterprising players might by that time already have purchased one or more of the supplements, or have gotten their hands on the small but growing number of newsletters and accessory products from Judges Guild or Tactical Studies Rules itself.
Or they were starting to buy and paint lead figures.
Not a bad way to while away the waning months of the Ford Administration.
(Later Edit: it's now clear to me that the heading picture is of the 6th printing, not the 5th. It's got that little star thing that says "Original Collectors Edition.)