Well...if you are a sucker for sci fi, you won't find it in any of those games really seeing as they are all forms of high fantasy. Ok Chrono Trigger is the closest thing, but not like Mass Effect or anything.
Anywho, I'd recommend Chrono Trigger and Final Fantasy Tactics, two of their greatest RPGs ever. Both have fun and interesting gameplay, stories, characters, ect...And personally, they are the best games on that list and can eat up a lot of time.
Chrono Trigger is like your typical JRPG (no that's not supposed to be a negative connotation) where you command a party and pretty much move from one plot point to another while still given some leg room to explore. Battles are turn based, but flow incredibly smoothly as they use the ATB system which is like turn based combat on fast forward. Combat is fun with the ability to combine character skills together to form some devastating and impressive looking team attacks. Oh and there aren't any random encounter or screen transitions for battles, you can see enemies on the map and avoid them if you don't wanna bother.
The game also has an excellent story and cast. Characters have vibrant and endearing personalities, the plot takes you to some wondrous and memorable locations (god I love Zeal), and the stories use of time travel is clever and interesting. It's deep and manages to do the whole "save the world" plot in a fun and interesting way.
Final Fantasy Tactics is a game that you can easily dump a hundred hours into or more if you wanted. It's a strategy RPG, like Fire Emblem or Advance Wars to put it rather crudely, like a board game if you will. You command a bigger party of characters that you form from recruiting enemies, story characters, or just hiring. Each character can be shaped into the fighter you want them to be through a HUGE set of customization options which can lead to some overpowered builds as well. There are over a dozen classes (mages, monks, ninjas, exc...) in the game and you can even assign a sub-profession to that character by augmenting a secondary skill set. So yea, you can have a White mage that also uses Black magic if you wanted to ect..
Combat is purely turn based through and through, but like I stated, it's like a board game where you move your pieces one at a time. When it is your turn, you move you characters on the grid to where you want them to be and select the actions (attack, items, ect...) before ending your turn to let the PC go. Battles can drudge on for a long time though given how difficult the game can be and the amount of strategy that has to be put into some fights. Still very satisfying game with a ton of options if you love just tinkering with character builds and what not. The game can be balls hard and just remember to keep multiple save files as being unprepared to some fights can back you into a corner.
Story wise, it's steeped in political, religious, and sociological themes all wrapped up in a lovely Renaissance/ Medieval style world...but with magic and all dat shit. Again, has strong characters and a deep plot which is full of interesting twists and introspection. A very good story that is still better written than some games/RPGs today.
So yea, that's my two bucks.
You can't go wrong with either game, but top notch experiences.
