[Error: unknown template qotd]
I'm going to go with The Two Towers. Because: Which two towers? There are at least five in the book (Orthanc, Barad-dur, Minas Morgul, Minas Tirith, and the tower of Cirith Ungol), and none of them stand out as the definite "two towers" the title refers to. Tolkien didn't even make up his mind as to which ones they were.

Not sure what I'd change it to, though. Maybe it should be "Something of the Something," since books one and three, and the entire series, are in that format. Or is that too Star Wars these days?

Part of the problem is the two halves ("books") of The Two Towers are so different. Book three is all about Rohan and the Ents, and book four is all about Gollum's appearance and then Frodo and Sam fighting giant spiders. (Uh, spoiler alert.) The two books don't even share characters! So there's not really one title that draws the two halves together, unless it's something boring like The Quest Continues.

Possible alternate titles:
Hobbits in Peril
People Not Being Dead After All
Never Get Involved in a Land War in Mordor
Are You There, Light of Earendil? It's Me, Frodo
They're Taking the Hobbits to Isengard! Gard! Gard! G-gard! Gard!
Uses for Taters
Eowyn: Pay Attention, She's Important Later
My Preciousssss