Is Denethor a main character? If not him, then my favourite is Gamling.

Those that come immediately to mind are sweet Rosie Cotton, well-meaning Barliman Butterbur and wise Famer Maggot. There are so many others, but I think these are my favorite minor characters.

Favorite non-main Character
 

I've been on Barrow Downs for 20+ years; this thread has been here since '05, and I haven't posted to it? Good thread-mining Alassë!

Books: That would be Halbarad, and by extension, the thirty other Dúnedain Rangers that answered his call to ride south to aid their Chieftain Aragorn. Added to them are Elrohir and Elladan, the Sons of Elrond who joined them on the journey. Of course, they all got replaced in the movie by an army of elves from Lothlorien.

Movies: Theodred. I like his part in the books as well. others... the squint-eyed Dunlending in the Prancing Pony, and of course, Rosie Cotton.

Uh...my namesake and Tar-Miriel... *vanishes beyond the door*

Lobelia Sackville-Baggins, hands down.

Yes, what a great character.

Despite her penchant for spoons, one can hardly help admiring a spunky, old hobbit-lady who would brandish her umbrella in the face of great danger. Even if she might be the sort one avoids at ordinary times.