[Mänwe]

A query such as this produces a great list of suppositions, thus here is my two pennies worth.

Gandalf's sacrifice would not even have been needed. They would not have passed through Moria but continued on their original journey through the mountain pass.

The events consequently at Amon Hen would have been a totally different affair. I would suggest perhaps even the entire fellowship would not have "broken". Frodo's admiration and love for Gandalf would have given cause for him to stay and not to leave.

Building on the point raised about the palantir, Aragorn would not have revealed himself through the palantir to Sauron. Thus Saurons attack on Gondor would have been delayed.

The list I am sure would be rather long if we all took the time to think of every possible angle. A concertina effect of occurences is bought to mind here.