My first encounter with D&D-style fantasy, and with role-playing games I guess, was not with D&D itself. No, the first time I encountered anything even remotely resembling an orc was in The Warlock of Firetop Mountain, and the Fighting Fantasy series of gamebooks that followed it.
Lo it was, some 21 years ago, that I found three books in the library of my primary school - The Warlock of Firetop Mountain, The Citadel of Chaos, and The Forest of Doom - the first three books in the Fighting Fantasy series. I was already fairly intrigued by monsters and swords and other such things, so I quickly snapped up the first of these and read it when I got home. It was a pretty mind-blowing experience.
My first adventure was far from auspicious. The set-up is that there's a warlock who lives inside the caves of Firetop Mountain, who has a whole lot of treasure that you intend to steal (presumably over his dead body). Of course he's guarded by all manner of traps and monsters... It's a classic old-school D&D scenario.
So my character went in, and very shortly encountered his first Orc asleep at the guard post. I'd never seen Orcs before in anything, but I quickly learned how to deal with them when the bugger woke up and attacked me - sword in the face! The adventure progressed, I fought a snake, found a key, and generally went the wrong way killing things as I progressed. After a harrowing section full of undead, with nightmare-inducing illustrations, I made it to the maze - and got hopelessly lost as teleport after teleport bamboozled me. I was unable to progress before bedtime claimed yet another adventurer.
From that night on I was hooked on fantasy, and D&D fantasy in particular. And even though the Fighting Fantasy tropes are obviously drawn from D&D, Ian Livingstone and especially Steve Jackson were always able to evoke a unique sense of the unknown. Perhaps it's the different medium at work, but magic in FF always seemed a bit more mysterious and arcane than in its RPG ancestor.
I'm still playing these things, and am currently engaged in an exhaustive exploration of book 2, The Citadel of Chaos. They're a godsend when a D&D group is unavailable, and those by Jackson and Livingstone are chock-full of old-school goodness.