The latest iteration of D&D, 4th edition, places its emphasis squarely on tactics, action, and flashy powers. In 4th edition, your character is a highly competent professional badass even at first level, skilled at chopping down foes and/or blowing shit up. You are, to quote Brick Top from Snatch, Muhammad "I'm Hard" Brucelee. "Big Damn Heroes" has become a shorthand for describing this approach, and it's a pretty useful one.
In the original version of D&D and its AD&D descendants, you were a lot more likely to be a loser at first level. Combat could be exceedingly deadly if you weren't careful, or if you just plain rolled poorly. If you wanted to make it to second level, you hired a bunch of goons as cannon fodder, tiptoed through the dungeon in fear, and ran away a lot. The game was designed by hardcore wargamers, who more often than not had a decent grasp of historical strategy and combat tactics. Somebody on RPG.net described the feel of early D&D as "Fantasy Fucking Vietnam", and again, that's not too far from the truth in my (admittedly limited) experience.
Now, I am not here to say one approach is objectively better than the other. As fun and as popular as the new game is, there has been a pretty sizable backlash against D&D 4th edition - which, as far as the mechanics go, really codifies what I would argue has been a slow but inexorable shift in tone from survivalist dungeon crawling to technicolor epic asskickery. In fact, I'd argue that the newest edition of the game finally allows your character to do some things that a lot of people expected the game to allow in the first place - and the artwork of much of the old material would have given you the impression that it did.
(I mean, check out that shit to the left. I'm still waiting for the Complete Wizards With Frickin' Lasers supplement.)
At any rate, a lot of people have decided to go back to earlier, more familiar editions of the game, or to take a new look at old books they'd never gotten a chance to until these heady days of cheap PDFs and open gaming licenses. I think that is laudable. There are a lot of cool old games out there that deserve to be played, and while I don't think I'd ever run the original version of D&D, I have played a bit of it, and I can confirm that it really does shine in the hands of a capable DM with a lot of time set aside for rules tinkering and world building.
But you know what? I'd be even happier if people would dust off other fantasy RPGs of yesterday and give them some new shine. So, coming up: a review of a new re-release of an old game that I feel really deserved it.