I am anticipating Skyrim to be the best yet by some way. My reasons:

1, Beth are well aware of what was wrong with oblivion despite multiple GOTY. They don't rest on this and will put things right with Skyrim. They are aware that Morrowind is the big fav also, and I imagine this game is likely to be Mor inspired rather than Ob.
2, The dev team have worked with the current gen hardware and software for nearly 6 years, and have admitted that there are better techniques used for maximising the capabilities.
3, The sheer excitment surrounding the game coming from the Beth camp is really encouraging, there are some things they are keeping back that will blow us away I recon.
Everything they have shown us so far are things that were somewhat expected, they had to reveal dragons in order to release the trailers, and theme.
4, The combat system, magic system and NPC interaction have all been improved.

On the downside:

We will have to wait and see how the removal of attributes and possibly spell creation effects the game, but I am seriously optimistic from what I have seen and heard so far.

where is the "I won't know until I play it" option? My answer will come once I play it. I have no idea how a game is going to be unless I play it. I have speculated before on games, and the ones I though were going to be bad ended up being good and vise versa.

I don't think that it is really fair to compare them, each one is a product of its time. :thumbsup:

If it gets released bug free, then yes I think it will be the best TES ever.

Fix'd don't forget Console

Things are looking good for Skyrim; if everything is accurate, it will bet out Oblivion (my top game of all time).

Where's the option: "each game is its own / has its own ups and downs (and can't be compared to each other at a whole)" or "they're all great !" ?

I definitely think it will be the best (so far, hint hint) in all aspects of gameplay and design. Skyrim will be amazing.