I loved Soul Reaver and Blood Omen and all of the interconnected stories in the series. I was seriously upset when a new game never came. However, it's one of the few games I still love to pick up and play occasionally. I was younger when I first started playing it. I definitely enjoyed the many puzzles and rich gameplay. Loved the voice actors. I can't even remember how many times I've played through them. Legacy of Kain was definitely a great series for the time and in my opinion worthy of another look.
I always loved Tecmo's Deception series, nothing like indulging your evil side by trapping someone's foot with a beartrap then dropping a flaming rock on them from the top of the stairs. Hopefully these are released eventually on the PSN.
After reading numerous entries I've dwindled down to one of my favorite RPGs as a child. Guardian's Crusade!!! The story is phenomenal and players really get to see the hero grow. One unique aspect about it, is the ability to use crafty "living toys" (summons) to help you battle with each having its’ own special abilities and perks.
Most games I really liked are well known, but there are a few which I might list here that are maybe not too much famous.
Bushido Blade 2 - a fighting game unlike any other. No energy bars, simple controls and a one hit kill possibility.
Oddworld: Abe's Odissey - one of the best puzzle games i ever played
Azure Dreams - I hate turn based RPGs, like Final Fantasy. Azure Dreams solved this in a way I have yet not seen in any other game
Alundra - I love RPGs with no stop action. This is probably the best one for PS1.
Broken Sword - There are few point and click adventures for PS1 that I know about. This one is great.
Catan - this PSN game has a few bugs, but I like the board game a lot.