[Child of the 7th Age]

Grounds keeper -- I agree with you. The Old Took and Bilbo might be tied for first. Remember the gift that Gandalf gave the Old Took?....Diamond studs that would button and unbutton themselves. Plus, if you look in Unfinished Tales, we learn that Gandalf has been keeping an eye on Bilbo since he was a young lad.

There was a long time after the Old Took's death when Gandalf did not visit the Shire or show off his fireworks to the hobbits. He came back to prod Bilbo into going on an adveture. After that adventure, Bilbo became the light in the Shire which Gandalf used to start knocking the younger hobbits out of their complacence, and their reluctance to head out on adventures. Who knows what would have happened if Bilbo had not been there to tell his tales, teach Sam his letters, etc.?

Frodo...Frodo was different. He was probably the hobbit over whom Gandalf shed the most tears. And I don't doubt that he did shed tears, since he had to heap such a great burden on him so that Frodo would never find true healing in Middle-earth or live a hobbit life again.