Suikoden 1 and 2 are way good. I'd play 1 first, as it's much cheaper than 2, and also because you might be lost as to who some of the people are in 2. They're both pretty easy as far as gameplay goes which is actually kind of nice, considering you get 108 characters. Suikoden is all about its' story. Suikoden 2 is pretty expensive but I think it's worth every penny.

Xenogears may very well be my favorite game ever made. It's got everything. I've seen someone describe it as the best book they've ever read, the best movie they've ever seen, and the best game they've ever played.

A couple other favorites:

Wild Arms 1 & 2 - Solid games.
Vagrant Story - Kind of difficult actually. If you liked Final Fantasy 12, you can kinda see where they refined some of the ideas from this game.
Saga Frontier - This one might be hit or miss. I like it though.

I hear a lot of good things about Chrono Cross but unfortunately I haven't played that one. I'm gonna get it though.