If you're interested in giving earlier editions of Dungeons & Dragons a try, I suggest you *also* get a copy of the 1981 Basic Rules, which may have the clearest explanation of some of the procedures those games follow.
Things like the procedures for exploration and combat are described much more clearly there than in OD&D or AD&D. You can then replace them with systems you like better, but it should give you a better feeling for the game. And the Expert rules add in wilderness travel.
I tend to like AD&D more than B/X due to the way it handles character classes, but I found the Basic rules invaluable in understanding the game.
I personally am not a fan of the Red Box of 1983; I'm sure it was very valuable to people learning the game then, but I found the 1981 set much easier to approach.
By "earlier" I mean 2E or earlier. 3E has its own procedures!
