I also really liked the SMT games that I've played, so far (Digital Devil Saga 1 & 2, Persona 3 & 4, and Nocturne).
I already have (and need to get to:) Persona: Revelations (PS1 & PSP), Persona 2: Eternal Punishment (PS1), and Persona: Innocent Sin (on the PSP), Strange Journey (DS), Devil Survivor: Overclocked (3-DS) & DeSu2 (DS) -as well as- SMT: Soul Hackers on pre-order...
...have ya played/can ya tell me anything about any of those?
Oh yeah - the only "SH" game that I haven't played yet is the prequel, Koudelka...and she's in the backlog, too
Coming from the more recent games as you are, most of those - esp. Persona and Persona 2 - will be a little bit of a system shock. While they won't be totally unfamiliar, things are generally less refined - much more challenging, fusion system is less user friendly and requires a lot of experimentation, demon recruitment can be pretty frustrating, and a lot of the answers that work really make NO sense at all, and collecting and exchanging rumors (which weren't part of later games) has a huge impact. Think of earlier Persona games like Nocturne and you'll do alright.
Persona: Revelations is the biggest oddity, in that the localization is pure and utter garbage. Tons of changes to character names and appearances, basically anything to make them non-Japanese, including one who speaks in ebonics. Honestly, probably the worst release Atlus ever produced, but thankfully, the PSP port does not suffer from any of this - if you don't have it yet, get it while you still can, and keep Revelations strictly for collecting.
Devil Survivor 2 isn't drastically difference from the first, so if you liked DS, you'll love it
As for Strange Journey, I unfortunately haven't gotten around to playing it yet (argh, backlog), but as with every SMT game, I'm sure it's awesome. From the looks of it, it's a throwback to the very earliest MegaTen games, at least in terms of the perspective you're playing from. Shame we never got them here.
And yeah, Koudelka's on my list too - prices started climbing a bit more than I'd like though, so I keep putting it off. Maybe I'll get lucky and find a near-mint copy under $30 one of these days.