I've become a big fan of old-school gaming.
I started playing D&D back in the late 70's, and followed the game as it progressed through its various incarnations.
When the original AD&D manuals came out, I quickly abandoned the old D&D to play the new and improved version. In fact, I scorned the later B, X, DA, and other "basic" Dungeons and Dragons material, thinking them suited only for those whose tastes were not yet refined enough to graduate to the better (advanced) rules. I followed D&D through 2nd Edition, where I began to lose interest, D&D 3.0 and 3.5, where it just became too complicated, and into 4E, for which I had high hopes ...
Having now returned to the old-school style of gaming, making use of the retro-clones appeals to me, for several reasons. First, I sold my original D&D boxed set, so the actual rules from the original set is largely unavailable to me (I do still have a copy of Greyhawk, though it's usefulness is limited due to the absence of the original three little brown books). Second, the editors of the retro-clones have done an admirable job of clarifying the original rules. Third, the retro-clone rules are available in pdf form, so it is fairly easy to obtain copies.
Of the retro-clones, my preference leans towards Labyrinth Lord and Swords & Wizardry. White box and OSRIC are appealing, although I prefer to use OSRIC as a resource rather than a rule-set, and White Box, while tempting, just feels a little too light (I quite enjoy the optional rules sidebars in that retro-clone however). I have heard some love for Spellcraft & Swordplay, but have not yet investigated that rule-set.
The one thing that the original White Box has over the retro-clones is the separation of materials into players' and gamemasters' books. From a publishing point of view, I suppose it makes sense to include the entire rule-set into one book. However, from a gaming point of view, particularly when trying to introduce new players to the original D&D, I would much prefer to have separate players' manuals and gamemasters' manuals.
It may just be me, but I still think part of the enjoyment of role-playing games is that the players do not to have perfect knowledge of the rules of the universe, nor about the monsters and treasures that are to found as they explore their game environment. I know one can split the Labyrinth Lord and Swords & Wizardry pdfs fairly easily, to create a players document, but if the editors intend to publish paper versions, I would love to see those published as separate players' and gamemasters' booklets.