The Shin Megami Tensei games are the core games of the series. They’re heavy ass first person dungeon crawlers featuring pokemon with their tits out. Super brutal and it’s pretty easy to get soured on the whole series if you play these first and aren’t inclinced to dungeon crawling.
Probably the best of the SMT games to start with is SMT Nocturne, for the PS2. It’s a bit more user friendly, having a third person perspective and the interface is slightly less retardo. You will pretty much need a FAQ to keep track of what skills to get when you level up so you don’t miss anything, and all in all it’s still pretty unforgiving, but doable.
If you get a taste for it you can try out the snes games that were translated, they’re pretty good, somewhat less complex but can kick your ass all over the place.
There’s two notable spinoff series: Persona and Digital Devil Saga.
Persona is probably the most userfriendly of all the MegaTen games, it’s pretty neat. Basically it’s a streamlined dungeon crawler, less dicking around with recruiting demons and instead having consistent characters. I kind of forgot how the earlier Persona games were, but Persona 3 is some weirdass dungeon crawler/dating sim/rpg THING which is awesome. Persona 1 is a bit eh, Persona 2 is apparently great but only Eternal Punishment was translated (basically the FFX-2 to Innocent Sin’s FFX), which bugs me enough to not play it.
Digital Devil Saga again does away with recruiting demons and has you playing with the same set of characters. I haven’t been able to find a fucking PAL copy, but if I could I’d probably have played the shit out of it. It’s more streamlined than Nocturne (skills aren’t GONE FOREVER if you miss them etc) and it looks pretty nice overall.
There are also a million other fucking spinoffs, ranging from CCGs to hitler demons and I don’t even fucking know, someone else should say what’s what because christ, there’s a lot.
So to recap, my suggestions for order of playing games: Persona 3 - FES (PS2), Digital Devil Saga (PS2), SMT Nocturne (PS2), snes games.
There’s another PS2 game, Shin Megami Tensei: Devil Summoner: Raidou Kuzunoha vs. The Soulless Army, but that’s even more of a bitch to find than DDS. It’s apparently pretty good though.
Enjoy getting into the most confusing series ever. Also, this is handy.