Some comparisons ...

Pick your favorite on the subjects ...

Graphics and engine

Overall Graphic experience by level design , complexity , technology behind and anything art or tech related for the period ...

Gameplay - magic - combat

Combat system variety , magic system variety , interaction with the attributes and classes and deepness of the overall system ...

Gameplay- details and interactivity

world detailing , interactivity with the environment and the other people , armour variations combinations , and moddability

RPG elements

attributes , perks , classes and so on

Story and quests

Main quests , subquests , number , density , complexity , realism etc...

LOL.You actually voted for Morrowinds gameplay.

Morrowind had the most interesting plot and politics with the house feud. And the Morag Tong are forever superior to the Dark Brotherhood. I enjoyed the exploration and mushroom houses with no stairs. But mechanically it is very very dated.

Oblivion is hard for me to say anything nice about. Even when it does have nice elements, such as the detail on the guild quests and interesting scenarios. But it feels dirty to compliment those.

However, Skyrim has those details in quests fairly beat so far. And much better plot, politics, and exploration though not up to Morrowind on those elements.

Graphics & Engine: Skyrim naturally.

Magic&Combat: Oblivion.In skyrim you cannot block if you have a spell in one hand.Big minus.

Details & Interactivity: Morrowind.Skyrim is filled with too much static objects.I was frustrated to notice I couldn't pick up lanterns.

RPG Elements: Skyrim.The main thing that makes this game stand out is this crafting stuff.Big addition,much bigger than what I was expecting.

Story and Quests: Morrowind.While Skyrim's quests are more fun due to NPC's being able to move and do stuff,the plot of the quests still suffer from Oblivion's "good guy syndrome",where the game tells you who is good and who is bad,and they are all black and white.Winterhold College is perfect example of this with its ridiculously obvious bad guy.

I voted for Skyrim on all counts.

Graphics and Engine; Really, is there any contest, here?

Gameplay - Magic - Combat; Again, Skyrim has the advantage of years of developer experience and gameplay refinement, here.

Gameplay - Details and interactivity; The only thing that Morrowind had more of than Skyrim was dialogue, and I think we can all agree that virtually none of it was interactive. Not to mention that NPCs literally did nothing but stand in one place 24 hours a day. As for details, it all goes back to who has the Graphics and Engine advantage.

RPG Elements; This is an ill-defined term, and clearly intended by the OP to be biased towards Morrowind. As Skyrim has the most detailed, large, and interactive world, I voted for it yet again.

Story and quests; This is where my own personal bias comes into play. I've been a Nord fan since Morrowind, so being thrust into their world and culture was about the best thing that could happen to me in an Elder Scrolls game.

morrowind people did almost nothing in town
in oblivion they walked around would be in a building but never did anything
in skyrim they actually do their job

Graphic is no discussion, details is also petty good in Skyrim, much more to do, this also give better role-playing.
Has not finished the game so not sure about story but so far it look good.
magic was better in Oblivion because of the spell editor, already people are complaining about weak mages.
In Morrowind magic was more broken than Skyrim.

Clearly Skyrim is the winner here.

Graphics and Engine; Skyrim. Looks soo unreal (in a good way). It's like you're instantly absorbed in a beautiful fantasy painting.

Gameplay - Magic - Combat; Magic hmmm.. Oblivion has spellmaking BUT it wasn't anything special. Magic in Oblivion all looked the same, all the spells were small balls of magic light, just with different colors. Skyrim's spells are fluid, limited number of spells true, but fluid. Morrowind... no comment. Combat... again, Morrowind doesn't compare to Oblivion, and Oblivion doesn't compare with Skyrim. Skyrim is the winner.

RPG Elements; A tie between Morrowind and Skyrim. Skyrim is simplified but in a good way. Useless skills (like Acrobatics) got slashed in order to give a more compact but fulfilling RPG experience. Morrowind on the other hand, had the advantage of choices, no matter how ridiculous they looked/seemed.

Story and quests; Morrowind & Oblivion probably have more Quests than Skyrim but you know why? Because the Skyrim we are playing now is the worst Skyrim version we will ever play, the 'Vanilla' Version (hate that word). It's the simple version. No DLCs/Expansions, no mods. It will only get better with time, although it already wins against both Oblivion and Morrowind for me. It will be colossal compared to them in a couple of months. Just wait and see.

Skyrim for the win.

While I enjoy Skyrim, there will always be a special place in my heart for Morrowind. The RPG elements alone make me feel like it's a superior game. The journal in that game was the best out of the three.

Some people haven't read the op properly.

Graphics BASED ON THE TECH AT THE TIME. Either Morrowind or Oblivion rate highest there, arguably Morrowind as it caused the most systems to chug. Skyrim was built for Xbox 360 and PS3 arhcitecture, ie,, the graphics are very roughly equivalent to the peak of a 3-4 year old PC's abilities. I'd have to say based on 'wow factor' in 2006 Oblvion takes the vote however.

Voted Skyrim for combat & magic gameplay, Morrowind for the rest (ie,, the most important elements).

Morrowind has the best questlines.

Skyrim is the best at everything else.

The Elder Scrolls IV: Oblivion is the greatest game in the history of the universe..

That's not a good thing. Graphics aren't simply about how hard the system has to work for it. Skyrim does its wonderful graphics very efficiently.

So inefficient optimization makes for good graphics, now? Absurd!

Clearly that wasn't my point (although it's certainly evidence).

Read the Op, he asked for the best graphics BASED ON THE TECHNOLOGY RUNNING IT AT THE TIME. Oblivion was probably the most revolutionary of the 3. Morrowind utilised increased viewing distances in an open world, also revolutionary.

Skyrim on the other hand, is NOT even remotely exceptional based on current PC capabilities.

Now, the art direction on the other hand! Skyrim wins for me, with Morrowind a close second. Oblivion was boring.

Again, Oblivion graphics weren't that great even when the game was released. The graphics engine was simply poorly optimized, which caused many PCs to struggle with rendering.

That's not how I remember 2006 but hey, each to their own. It was certainly better than the DX9/DX10 processes they've got running on Skyrim currently.

It's to be expected though, the consoles are both what, 6 & 7 years old respectively? There's only so far they can go before they conk out under the strain.

My row:

Graphics and engine
Skyrim (57 votes [80.28%])

Gameplay - magic - combat
Oblivion (9 votes [12.68%])

Gameplay- details and interactivity
Morrowind (17 votes [23.94%])

RPG elements
Morrowind (29 votes [40.85%])

Story and quests
Morrowind (18 votes [25.35%])

Surprisingly few votes for Skyrim, even though I absolutely adore it!

It all goes back to what you define by "most graphically impressive." Is it the game that requires the most CPU/GPU power, or what you consider to be the most visually impressive?

The former option is largely dependent on a game's optimization, while the latter is almost entirely subjective.

That's not what I said. I'll leave you to figure it out.

As of right now, i'd go with (in order of preference):

Morrowind
Daggerfall
Modded Oblivion
Skyrim
Vanilla Oblivion

I know that it's not what you said. What you said was almost entirely irrelevant.

Graphics art , atmosphere imersion, characrer creation , crafting and quests to me skyrim wins. Rpg elements interactivity with items spell system , attributes system and armour system morrowind wins.... So for meis mostly a skyrim vs morrowind ....

Visual impression is made of two elements actually,IMHO.

1-Design of the scene/object
2-Rendering of it.

I personally never judge graphics of the game by its design,because usually this refers to rendering quality.They show off the graphics by showing water,distant land,lightning,etc. screenshots.In the rendering aspect Skyrim wins naturally,but should it be the design we're talking about,I know of no game that can top MW.I would love to see MW design with Skyrim render and than I'd call it over-epic.

Indeed. When it comes to design, though, Morrowind *should* have the advantage; the developers had the distinct pleasure of designing a world that was meant to be odd and alien. Every one of Morrowind's successors have taken place in less visually interesting areas, with the exception of the Shivering Isles (Which I found to be at least equal to Morrowind's alien visuals, possibly better).