Has there ever been a mightier villain than Thanos in Marvel History?

[T.M. Anthony]

The celestials spring to mind.

These guys are so bad ass they give Galactus problems. Surely Thanos would have a tough time.

[AntiPatriot]

People give Galactus too much credit.
Yes, he is very powerful, but compared to Thanos with the IG/Heart, he is nothing but a little insect.

And the villain/force of nature thing:
The villain appears once Galactus is dead (Abraxas).
So yes, Galactus is a needed force of nature.

[Mutant God]

Maybe Nemesis the thing the Infinity Gems are from, but is she canon?

[Shingen]

The Death Celestial!

[E. Wilson]

Are we counting Thanos' ability to bore entire planets to death with his repetitive philosophical ramblings as part of his might? Because he'd probably win at that point, LOL.

(In fairness, I like Thanos well enough when he actually does things, but when he starts speechifying, I just want to fall asleep.)

[AntiPatriot]

Oh c'mon, at least his dialogues have some intelligence in them, other than Darkseid's constant
*A god I am. There is only Darkseid. Insect. I shall bound you all to my will* blablabla.

[CjP]

In theory I'd agree, but only because he's just shy of the line (power-wise) where good and evil cease to matter.

[dupersuper]

Stupid work computer...

Oh c'mon, at least his dialogues have some intelligence in them, other than Darkseid's constant
*A god I am. There is only Darkseid. Insect. I shall bound you all to my will* blablabla.

You gotta' love the "Darkseid is" bit from JLA though...

In theory I'd agree, but only because he's just shy of the line (power-wise) where good and evil cease to matter.

"Above all else, a god needs compassion." - James T. Kirk

[E. Wilson]

Oh c'mon, at least his dialogues have some intelligence in them, other than Darkseid's constant
*A god I am. There is only Darkseid. Insect. I shall bound you all to my will* blablabla.

Well, to each their own. Thanos' rants always struck me as the worst type of self-absorbed naval-gazing. Give me Darkseid any day; dude gets stuff done.

[Mutant God]

Onslaught maybe

[berk]

Thanos was an excellent villain in Starlin's first Warlock story but has become a little tiresome to me over the many years since then. The Magus was his match in that story, so there's another candidate. The Celestials aren't villains.

I always thought Dormammu was one of, maybe even the single most impressive Marvel Universe villain, although as always, of course, it very much depends on how the particular writer handles the character. Umar as well, since she's pretty much his equal.