[The Squatter of Amon Rûdh]

Yes, we have digressed a little...

I can't see any reason why one couldn't wear more than one of the rings of power, although there is hope for those who don't like jewellery. All The Silmarillion has to say on the matter of the powers of the Three in general is that

"...of all the Elven-rings Sauron most desired to possess them, for those who had them in their keeping could ward off the decays of time and postpone the weariness of the world."

Which implies to me that one doesn't need to wear one of the Great Rings to exercise at least some of its powers (this is borne out by Frodo's experiences with the One, which exerts its force on him even when he isn't wearing it). One merely need have it in one's keeping, and Sauron at least had hopes of using all three (in concert, presumably, with the One). Even evil fades in Middle-earth.
The question is: What's the point in having all of them? Presumably the Three have slightly different preservative powers, as the following is said later:

"...the Ring of Sapphire was with Elrond...upon whose house the stars of heaven most brightly shone; whereas the Ring of Adamant was in the Land of Lorien where dwelt the Lady Galadriel...and she was the mightiest and the fairest of all the Elves that remained in Middle-earth."

and later, Cirdan's words to Mithrandir on the passing over of Narya:

"Take now this ring, for thy labours and thy cares will be heavy , but in all it will support thee and defend thee from weariness. For this is the Ring of Fire, and herewith, maybe, thou shalt rekindle hearts to the valour of old in a world that grows chill."

What I see here is an implication that Rings work best when used by people whose personal attributes complement their powers, but that these powers are enhanced by the action of the Rings. For example, Gandalf's worth listening to in any case, but Narya enhances his credibility and Galdriel is beautiful and powerful anyway, but Nenya gives nature a hand.

So that's the long version of my opinion: Yes, you can probably wear more than one of the rings (provided you're up to it, of course), but I don't think that everyone would get the full benefits of all three.

As for the other rings, I don't know enough about them to make a decent guess, although I postulate that the Nine have identical powers, and that most of those are for Sauron's benefit.

[ January 11, 2002: Message edited by: Squatter of Amon Rudh ]