The best Zelda game to start with in this day and age ironically might just be Skyward Sword. This depends on a number things, primarily whether or not Nintendo will continue with their casual difficulty and casual playstyle. I've heard many quips from fans that SS was the future of Zelda, and fight as I might, Nintendo might think so as well. I recommend everyone start with SS and get accustomed to it; Zelda won't change outside of too many borders if SS indeed is the future of Zelda.
Putting baseless rumors aside, I believe people should start the series with Ocarina of Time 3D because, although it's an old game, it still is the pinnacle of Zelda and the difficulty is actually pretty similar to the likes of modern Zelda. Fun stuff all around.