I always title. Always. Every time. I haven't published a single photo marked as "untitled." If it's a photo that involves a dramatic depiction of people, I come up with a title that adequately inhabits the scenario. If it's a set of posed portraits, I will use the subject's name or initials and a numbering index so I can refer to the photos later.
I agree that words often constitute a poor attempt to do what photos accomplish more efficiently, but the idea that the right name weakens a work is untrue. If a current title detracts from a photo's value, you've chosen the wrong title. A good title can be difficult to construct, but it will be worth the effort: it will finish a good photo, give it an individual polish. If successful, a good title can prove that your photo deserves to be remembered in a name.
Sure, van Gogh's "Wheat Field with Crows" is the most literal of titles. However, the painting is so great that there can never be another "Wheat Field with Crows" that doesn't infringe on that name. How can one say that the name detracts from the work? What would be the point of preferring that it be called van Gogh's "Untitled"?
On the other hand, I don't consider captions all that important as part of the work. I think they're great for reference, for letting the viewer know where the photo was taken. However, because the photo is a record of a moment that can't be repeated, and, if good enough, conveys specific emotional value, I don't see any point in explaining anything. It is romantic to think that "Wheat Field with Crows," because of its magnitude, was van Gogh's last painting. It's so good that we may call it the apex of artistic skill. Is it any wonder then that, technically, though it was NOT van Gogh's last painting, we desire more than anything to give it that story, the value of a whole life? It's been determined that several subsequent, less spectacular paintings of the same wheat field were probably van Gogh's last -- but we are always disappointed to think less of "Wheat Field with Crows."