The game that introduced me to the RPG genre and got me hooked on it was Final Fantasy II for the SNES (FF IV by the Japanese numbers). In retrospect, it was a great introductory RPG. First off, Final Fantasy II was a very simple game, since there was no complex character customization. Instead, characters only gained preset abilities as they leveled up. Combat was as simple as using the Fight or Magic command to defeat enemies. Now then, the American Final Fantasy II was a stripped down version of the original Final Fantasy IV with reduced difficulty, but I think that actually made the game a better entry level RPG. I remember having a lot of trouble with certain bosses (most notably Rubicant) when I first played Final Fantasy II, while these days I can beat those bosses easily, even on the original harder difficulty setting. The easier difficulty setting was a lot more forgiving for a rookie like me who accidentally de-equipped his main character's sword before ever getting into a fight. In particular, I found the early game strategy guide built into the game's manual to be very useful in my younger days.
These days though, there is a strong tendency for RPGs and other videogames to be made with experienced players in mind. Games have much more complicated gameplay these days, particularly when it comes to character customization and combat. Final Fantasy X's Sphere Grid is a much more complicated game system than most earlier RPG systems, with a much greater ability for the player to gimp his own characters. Most games have a lot more limited tutorial support for new players as well. The very useful "Beginner's House", where the player can talk to a concentrated group of NPCs to learn about basic game mechanics, from the early Final Fantasy games was discontinued in the series after FF VII. I haven't seen a full early game tutorial included in the game manual since Lunar: Silver Star Story Complete (and the practice was becoming rare even in the SNES days).
Even today, I have trouble thinking of a really good introductory RPG. While Dragon Quest VIII is almost as simple and straightforward as an SNES RPG, it is also really difficult in the early part of the game, and has enough customization that I gimped my characters on my first attempt at it. Final Fantasy XII has the complexity of the Gambit system, the added problem of having to deal with real-time monster encounters, and a reliance on lots of sidequests and level grinding. And the further one goes from the big name RPGs, the more likely one is to encounter niche RPGs that differentiate themselves through increased complexity aimed at genre veterans.
Today, remakes of old games are the only place someone is likely to find a really good entry level RPG. And even then, the upcoming DS remake of Final Fantasy 4 has been advertised as having increased character customization and increased difficulty compared to the original version. While those factors do appeal to me at my current dedication to the RPG genre, I can't help but wonder if it will still be as good of an entry level game anymore. With the recent expansion of the videogame market to tons of brand new gamers, entry level RPGs are really needed now.