The Lord of the Rings Discussion, Book II, Chapter 1

[Telcontar_Dunedain]

It couldn't have been one of the seven, the three or the nine. In the Shadow of the Past or the Council of Elrond, Gandalf says the others all had a specific gem but not so the One.

[The Gaffer]

Originally Posted by Nurvingiel

In addition to his other tasks,

What was more important than saving ME from eternal darkness? Taking his robe to the dry cleaners?

[Durin1]

But Gandalf only entered into Dol Guldur (in disguise) to find out clearly who was residing there. It was initially believed that a Ringwraith had (again) taken up a position there.

Therefore it was chance that Gandalf met Thrain there and chance that Thrain, in his dying state, mentions something about how the "greatest of the Seven has been taken" [paraphrased].

It is important to remember that up until then, Gandalf had no reason to go into ring-lore: that was Saruman's speciality. Therefore there was no incentive for him to learn any more about the Rings of Power: He would know about the 3 and the 9; he believed that the One had been lost.. so there was no significance, at this stage, about the Necromancer having captured Thrain's ring. It is only in 2941 when he finds Bilbo getting up to tricks with a golden ring that he slowly begins to suspect more and researches for himself.

[Nurvingiel]

Originally Posted by The Gaffer

What was more important than saving ME from eternal darkness? Taking his robe to the dry cleaners?

Lol, maybe he was Gandalf the Grey for a reason. I meant other ME saving tasks, before he knew what the Ring was.

Originally Posted by Durin1

Therefore it was chance that Gandalf met Thrain there and chance that Thrain, in his dying state, mentions something about how the "greatest of the Seven has been taken" [paraphrased].

I think you're right about that, and about Ring-lore. I bet Saruman would have actively (but subtly) discouraged Gandalf from looking into it too, as he was becoming more corrupted. Remember how he delayed in attacking Dol Guldur. Gandalf reflects later that he had been stalling (paraphrase).

[The Wizard from Milan]

My question
Why was Bilbo not present at the banquet? Bilbo himself gives a justification (I can't remember it, but that is not my question). My question is: why Tolkien decides not have Bilbo at the banquet?

[Earniel]

My answer would be that Tolkien wanted to have the reunion of Frodo and Bilbo at a better time. On the banquet he had other things he wanted to give some lime light, like the conversation between Gloin and Frodo. If Bilbo had been at the banquet such events would have taken a back seat to Frodo seeing Bilbo again. It also spreads the different events better storywise. The banquet scene would have been overloaded with things that had to happen there otherwise.

Oh and welcome to the Entmoot!

[Durin1]

In the Hall of Fire, Bilbo says of himself that he doesn't go in much go to banquets and other things these days. I think it is just Tolkien showing the reader that Bilbo is getting old.