I'm a little late to the party.
For PC, there's little left to be said besides PS:T. Sabathius is totally correct about Star Control 2 though. Just avoid SC3.
For console... I'll add my vote to Suikoden, except 4 (which blew, IMO).
I'm an SNES-era (4,5,6) FF fan (though my first was FF1, sorry Darkwolf), especially with regards to the stories. After that, I'm not so much a fan of the stories, though 9 is alright and 10 at least had excellent gameplay.
Final Fantasy Tactics has an excellent story... if you can stand the absolutely shoddy translation. The gameplay leaves a little to be desired, but is good enough.
I'll throw in Lufia 2, especially the ending. Also, I'll mention Wild Arms 1 and 2 as having decent storylines as well.
Really, the best console game ever though is Chrono Trigger, hands down. It's a bit on the easy side, but the story makes a huge impression and the characters are well done.
Xenogears, on the other hand, I can not disagree with more. I found the gameplay very tedious and boring, to the point of actually detracting from the story. As others have mentioned, it completely broke down in the second half. IMO one of the most overrated games ever.