Games in English:
Growlanser Generations - PS2
This is Growlanser II and III packed togheather.
They are SRPGs with a rather nifty Semi-real-time battle system. Like Every game in the Growlanser series, you can chase the girls (or befriend the guys) by picking options and finding special scenes. II and III are actually the weakest points in the series, but still great games and different (and better) then most SRPGs in the console market. And Satoshi Urushihara’s designs are as beautiful as ever.
Vanguard Bandits - PS1
A solid fantasy with Robots SRPG. There are 3 different story routes and 5 endings. The girl you end up with is determined by which ending you get.
Thousand Arms - PS1
A traditional RPG with a very dull battle system. However you do actually go on dates (fully voiced) with typical B-game choices to choose from. Good dates get her likeing you more. But… I do NOT recommend this game, because there is only ONE ending. And its a crappy cop-out ending that will simply anger you.
Games in Japanese:
There are tons of them so I’ll only list the best.
Langrisser III,IV,V (various systems)
Langrisser was the first series made by Career Soft (developers of Growlanser). L-IV is simply as good as an SRPG can get, everything is perfect. In III-V you can try to woo the Urushihara beauty of your choice. If you whish to invest in this series, the Saturn versions are the best overall.
Growlanser I,IV,V, (VI is comming soon).
Ironically the Growlanser games that didn’t make it to the English market are better then the ones that did. So enjoy Generations, then play these for the real magic 
Black/Matrix I/AD/+(Sat,DC,PS1)
Very dark themed SRPG that is extremely popular. You get to pick your heroine from the start and it changes the game acordingly.
Black/Matrix II (PS2)
Sequal to the above, good game but lack of Voice Acting hurts a lot. Here, their are multiple paths depending on your actions, the path also decides which girl.
Summon Night 3,4 (PS2)
Made by the same team as Black/Matrix but published by Banpresto so a much bigger budget. Here you can talk to characters and if they like you enough, you can get endings for every single one.
There are many more, but the above are my recommendations (except for Thousand Arms, great game until the end ruined the whole thing). If you want games in English, Growlanser Generations is the best your gonna get, unless I’ve forgotten something (quite possible).
If you have questions please ask 