Of the pre Psychedelic Beatles, Revolver down, I would pick Revolver, but I think that side one of Rubber Soul is better than any one side of Revolver, Revolver just has both sides.
But enough about that, Morrowind was their pinnacle.
I think The Beatles were well into their psychedelics by the time they finished recording Revolver. That's what Tomorrow Never Knows tells me, anyway.

Not to mention previous songs like Day Tripper.
70% filler...Wha? Piggies, Everybodys Got Something to hide..., Savoy Truffles, and Rev 9 (arguably), were the only filler songs.
Edit: Wild Honey Pie was filler as well.
Everybody's Got Something to Hide is an awesome song!
Couldn't help getting involved with the Beatles discussion there. Anyway, I honestly don't think Bethesda can or will bring us the "Citizen Kane" of gaming - or Sgt. Pepper's if you will, but to me that album didn't revolutionise much, it only cemented and brought the emergent psychedelic rock scene to the mainstream. By that notion, Bethesda have already had their Sgt. Pepper's in my eyes, whether it be in Morrowind, Oblivion or Skyrim, as each has contributed in part to bringing sprawling first-person RPG's into wider recognition. The "Citizen Kane" of gaming would present a whole new style of gaming; this could arguably be found in a multitude of indie games, whether you're talking about downloadable games for consoles like Flower or obscure games created by small developers for the PC. There are tonnes of games out there which innovate and don't revolve around "mortal combat", you just have to look.
I do honestly believe someone in the next thirty years will innovate gaming so that it becomes a valuable art form. It would no longer be "gaming" of course, but instead a multisensory interactive experience. Currently, visual art has much more room for freedom than gaming. Orson Welles was in the position where he could use light and cameras however he wished. No matter how hard indie developers try - especially for consoles - they're still limited to the medium of a couple of buttons or keys in order to make their game an experience which would not be better translated as a film. Now, of course a game developer could create an innovative game of the same caliber as the masterpieces of mainstream cinema - they can still manipulate the player visually, audially, and even tactilely to some extent if you consider Dualshock and suchlike - but why should they? Films are far more accurate in achieving their impact on the spectator because everything is presented how the director chooses. You couldn't put a gamer in the position of Orson Welles in Citizen Kane because then they could just run around [censored] [censored] up, which ruins the immersion entirely.
When we start standing in immersion tanks that manipulate us visually, audially, olfactorily and tactilely, covered head to toe in various nodes, then things will be different, whether it be interactive, like a game, or not, like a film. I'd hope there'd be less "mortal combat" for one, otherwise we'd be world of very sick puppies. Gaming would certainly change then, but I doubt the original form of gaming - manipulating a screen with a controller with a few buttons on it - would ever die out, it'd only expand: bigger screens, louder guns, more ostentation! Artistic gaming wouldn't be addictive. It wouldn't be as fun. A human becomes addicted to the rewards of habitually pressing buttons on a keypad. Call me a philistine, but I've rewatched dumb films that make me laugh like Wayne's Would a great many more times than I've watched films which innovate and could honestly alter a society's collective consciousness. Laughter is much more addictive than brooding over society's ills. So is shooting the head off of a rancid zombie with an RPG.