Xenogears and Xenosaga
XG has a very long disc 1. XSI is episode 1 of the Xenosaga story and has a lot of cut-scenes, after beating XSI, you would want to follow up with XSII and XSIII. They are both high quality games with fantastic music and epic well written storyline. I suggest that you play a bit of XG and a bit of XSI and see which one you like better and then continue to finish the one you like and then play the other one afterwards.
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KOS-MOS: There is no connection between my current systems and your life functions.