The best game to ease into the genre would be one of the Shin Megami Tensei series [Specifically, Persona 4]. The reason for this being, they're fairly easy to grasp control-scheme wise [The only real complication being the relationships, but if you've played a dating sim before you've got it down], and they have stories good enough to drag you through the heavy cutscene-to-gameplay ratio which is the cornerstone of all JRPGs [Not as heavy as MGS, though].
After situating yourself with the completely different genre [For there is really no other genre like it], I'd suggest going with either Kingdom Hearts or Final Fantasy, not both at the same time. The reason for this is: Kingdom Hearts' story is far more lenient than any other JRPG series you can care to name, and each Final Fantasy game has a self-contained story [It doesn't carry over to the next, or come from the last] with the sole exception of direct sequels like X-2 [Which I liked, by the way], meaning you don't have to do any backstory research if you want to jump in the middle.
That should settle you in, and once you've got that you can go to other games such as the Dragon Quest series, the Breath of Fire series, the Tales series, and the Suikoden series. Steer clear of things such as Star Ocean and Xenosaga until you've gotten used to the genre, because Xenosaga is just as if not more wordy than MGS4, and there are three of them. Star Ocean isn't as wordy, but it's got more twists than a crazy straw.
Each JRPG series is different, some relying more on story than combat, some taking new stances with combat than story. Lost Odyssey is a fantastic example of current-gen RPGs, with a neo-classic control scheme [New take on an old thing], and a fantastic story. I found myself looking more for pieces of Kaim's past than for items or treasures, and pushing onward prematurely to get to the next bit of story to find out what happens next.
And the most important thing to keep in mind is that most JRPGs are very emotional experiences. If you're a jaded narcissist, probably not the genre for you. JRPGs demand that you invest yourself into the story, and they'll tug your heartstrings more than once. If you're not a bit of a romantic, you'll get turned off fast.