Which of the Fellowship would have gone ring mad?

[Oddwen]

Another thing to consider would perhaps be who saw it at the Council - Merry, Pippin and Sam did not, and neither Merry nor Pippin saw the Ring at all. (Save for the one time Merry saw Bilbo use it to escape the S-B's) Frodo, in the face of all gathered, actually said that it should go to Aragorn.

'Then it belongs to you, and not to me at all!' cried Frodo in amazement, springing to his feet, as if he expected the Ring to be demanded at once.
'It does not belong to either of us,' said Aragorn, 'but it has been ordained that you should hold it for a while.'

(emphasis mine)

Why should he expect that? Did he learn something of the nature of Strider while travelling with him?

[Voralphion]

Aragorn may have been ablr to resist it because he grew up fearing the power to become King never mind the power of the Ring.

He was never scared of 'the power' of becoming king, that was an invention of the movie.

Aragorn probably would have been able to resist the ring for quite a while, since it was offered freely to him on a few occasions and resisted it knowing of its power and dangers.

[Nilpaurion Felagund]

Many of you said Aragorn would have fallen first, due to him being a mortal, but Gandalf and the other Istari were

...clad in bodies as of Men, real and not feigned...

(UT IV 2 - emphasis mine)

Hence, the temptation of the Ring would have been equal on both - probably more so on Gandalf, since he was bearing a heavy burden, and anything that could have lightened such a burden would have been tempting to him.

[samwise8504]

i also think pippin would of been next because of his curiousity e.g. the palantir, Aragorn would of been next after pippin because men are easily corrupted by the rings power and he has isildurs blood in him and the blood of numenor.