You could try out the DS remake of Dragon Quest VI if you haven't already--one of the greatest JRPG's ever, IMHO. Also, seconding the recommendation for Fallout: New Vegas (it's not really an FPS at all). You should really look for one the radio extender mods, they give the game a lot more life. If you haven't already you should also play KotOR 1 and give II chance, it was prepared to be one of the greatest CRPG's ever, and you can kind of see it if you use one of the content restoration projects, which are really good.
Also: Planesacpe: Torment. Play it. Now. No one can properly call themselves a Role Playing gamer until they've beaten this. Some other good classics, inculde Arcanum, the first two Fallouts (III is utterly missable), and Baldurs Gate I and II, all of which you can get dirt cheap (and on sale) on GoG.
If you like 4x's, you should also really cheack out Masters of Orion I and II, which they have on GoG as well.