Sue isn't one to be taken lightly. Her husband is the most intelligent man on earth, and her son is one of the most powerful beings in the universe. And she rules the roost.
And Xavier has stood in front of the Goddess with the Cosmic Egg. That doesn't matter. You're comparing apples and oranges. If you mention combat as a measure of willpower, then Xavier doesn't stand a chance compared to the others, because he doesn't often engage in combat. But there is a reason it's said that Xavier has the strongest mind on earth. He's not been the most powerful TP for years now, but he still runs circles around almost the entire MU. Look at what his subconscious created.
I think TPs in general probably have the strongest minds, because that's their province. Some are more sensitive than others, but one rarely encounters a weak-willed TP. Xavier and Jean have both traveled into death with people on more than one occasion. It's one thing to watch it happen, but something totally different to be in the mind.
If we were to put these four people in a room where they could only engage in psychological combat, Xavier would cream the rest.
Now if it were combat, I think it would depend on the situation. For example, if Franklin were in trouble, almost nothing on Earth would stop Sue.
In the poll I vote for Cap, man's got balls of adamantium. Next the prof, lets face it he's been fighting a losing battle for over half his life and simply refuses to quit. DD comes next, radar sense be dammed the man's blind and still beats up on super villians. Sue generally has back up so I think going solo she'll have the least will power.
Outside the poll, Doom and Strange in a tie for first place
ok let me differentiate willpower and courage
COURAGE= cour·age
n.
The state or quality of mind or spirit that enables one to face danger, fear, or vicissitudes with self-possession, confidence, and resolution; bravery.
^^^this is what cap is made of. and apparently he got lots of them or should i say he has "balls of adamatium"
WILLPOWER= will·pow·er or will pow·er
n.
The strength of will to carry out one's decisions, wishes, or plans
now this is what charles and DD (sue in some cases) have that keeps them going,keeps them from giving up.
examples:
a.)charles with his incapability to walk yet his works are on a global scale, and the fact that he will never be fully accepted without prejudice but keeps on fighting for them
b.)DD With his vision problem
c.)and Sue not giving up for anything to rescue her children
got it?