[Ancalagon'sFire]

The staff in the hand of a wizard may be more than a prop for age' said Háma. He looked hard at the ash-staff on which Gandalf leaned.

It is an interesting choice of words Háma uses and probably the most adept observation he could make. The term ash-staff also intrigues, for one wonders where the staff originates from, was it brought with him across the sea, if so it is ash from Valinor and made from the song of Yavanna herself. If not, it originates then in Middle-Earth and is but a stick until it finds itself in the hands of a Wizard. The two seem intertwined, made for one another but by whom? Is it carven by Elves or by Aule himself? There is clear reference in Unfinished Tales describing Gandalf's arrival:

Others there were also: two clad in sea-blue, and one in earthen brown; and the last came one who seemed the least, less tall than the others, and in looks more aged, grey-haired and grey-clad, and leaning on a staff.

It may be safe to assume he brought it with him, unless someone other than Cirdan brought it to him for the journey across the sea, having first been carved in Middle-Earth. I suspect however he has brought it with him, as did they all. Yet, when Gandalf strayed out of thought and time, and wandered far on roads that he would not tell, he is returned naked and conveyed to Lothlórien where he is clothed in white. Where does he regain his staff on this occasion? Gandalf is most associated with the staff, by Men, Elves and Dwarves alike, but that is most likely due to his constant relationship building among each race.

He raised his staff. There was a roll of thunder. The sunlight was blotted out from the eastern windows; the whole hall became suddenly dark as night. The fire faded to sullen embers. Only Gandalf could be seen, standing white and tall before the blackened hearth. In the gloom they heard the hiss of Wormtongue's voice: 'Did I not counsel you, lord, to forbid his staff? That fool, Háma, has betrayed us!' There was a flash as if lightning had cloven the roof. Then all was silent. Wormtongue sprawled on his face.

Wormtongue's comment is clearly the counsel of Saruman who knows such things. The staff is a conduit for Gandalf's power, without which he is but an impotent fool. There is an intriguing insight into Tolkien's deliberations about Gandalf's staff taken from Book of Lost Tales 2 in which he makes several varying references to the power of the staff.

'Well, that's that,' he said. 'It was all I could do. I expect I
have buried Balin. But alas for my staff: we shall have to go by
guess in the dark. Gimli and I will lead.'
They followed in amazement, and as they stumbled behind he
gasped out some information. 'I have lost my staff, part of my
beard, and an inch of eyebrows,' he said. 'But I have blasted the
door and felled the roof against it, and if the Chamber of
Mazarbul is not a heap of ruins behind it, then I am no wizard.
All the power of my staff was expended [?in a flash]: it was
shattered to bits.'

Of course, this is not the finished product and doesn't make the final version which we see in Fellowship of the Ring;

Suddenly at the top of the stair there was a stab of white light. Then there was a dull rumble and a heavy thud. The drum-beats broke out wildly: doom-boom, doom-boom, and then stopped. Gandalf came flying down the steps and fell to the ground in the midst of the Company.
`Well, well! That's over! ' said the wizard struggling to his feet. `I have done all that I could. But I have met my match, and have nearly been destroyed. But don't stand here! Go on! You will have to do without light for a while: I am rather shaken.'

It is clear however that the staff has been employed in the destruction of the chamber and as such the light has been lost. These references seem to give some indication as to the power within the staff. I would suggest that the staff itself is made for each Wizard, possibly corresponding with their respective colours/skills and each ordained with specific powers exclusive to the nature of that Wizards colour/skill. It begs the question; Does a Blue Wizard have a Staff that harnesses 'water' and if so were they choices of Ulmo? The Brown Wizard, Radagast, does his staff induce growth, control over the flora and fauna of the Land? Saruman, it would indicate his seems more inclined towards vision, of revealing secrets and thus controlling (at least attempting to) the minds of others? Although there is clearly much more to his make-up than that, not the least his control of the weather while the fellowship attempted the crossing of the Misty Mountains. As for Gandalf he says himself: `I am a servant of the Secret Fire, wielder of the flame of Anor. You cannot pass. The dark fire will not avail you, flame of Udûn. Go back to the Shadow! You cannot pass.' Most references to Gandalf's Wizardry seem to point to fire, flame or light. There is no doubt each Wizard has some innate ability to control or manipulate the elements which one would suspect is the gift of all Maiar since they had a part in the 'song' and their creation. The significance of a 'wood' staff and how power is divined through it, I am not so certain.
As always, these are mere observations and speculations on my part and open to the utmost scrutiny