It would be easier to make a recommendation if you specified some kind of a style preference. As far I can see, you've played pretty much every noteworthy RPG released in the last ten years, but there are many, many classic RPGs that may be of interest to you. But, since I consider most RPGs a big pile of poo, I'll just restrict my recommendations to a few select titles that I consider to have aged exceptionally gracefully, even putting most of today's "RPGs" to shame.
For starters, if you're into sandbox RPGs, you owe it to yourself to try Darklands and Daggerfall, both great games and both so far ahead of their time that the RPG genre still hasn't quite caught up.
Of more narrative-oriented RPGs (and thus probably more familiar to us who have grown up with the likes of PS:T and Fallout) I can recommend Quest For Glory series (at first glance, yet another goofy Sierra adventure game... that is, until you notice the beautiful roleplaying mechanics bursting from every pore), Betrayal at Krondor (written by a profeshunal author) and Albion (an obscure German sci-fi RPG with intriguing setting, nice hand-drawn graphics and turn-based combat, unfortunately marred by awful first-person exploration).
Most old-school roleplayers would now recommend a couple of dungeon crawlers like Wizardry or Might&Magic, but since I couldn't give two shits about dungeon crawlers, I'll refrain from doing so. Besides, there have been so many releases in this category that you could alphabetically play through each and every one of them from this day till kingdom come and find yourself still playing Aleshar: Azure Armor of Arborean Ancients on the day of the Armageddon.
Finally, no list of recommendations is complete without the ubiquitous Ultima, so be sure to give that series a spin. The first three installments are plain old dungeon crawlers, so feel free to skip those and move right onto the real thing - namely, Ultima IV-VII. Even though many aspects of those games may seem laughably outdated or cliche in this day and age, keep in mind that they are the most genre-defining releases in the history of CRPGs, so much that modern RPGs probably wouldn't exist without their influence. And if you're like me and find yourself bothered by the antiquated interface and visuals, there is always the Ultima V remake (called Ultima V: Lazarus) using Dungeon Siege engine, and I hear an Ultima VI remake is in the works as well.
Oh, and I hear Wasteland is quite popular among talking lizards, so be sure to give that a try, too.