Bantam Books, you're on notice (as Stephen Colbert would say). Why are they the target of my (righteous or otherwise) ire? Because they publish the Bryant & May novels by Christopher Fowler -- a series of seven books so far -- and they've already changed the spine design THREE times. To whit:
The first two books in the series: Author above, title below in thick caps, and a box around. Even here, they have two variations on a theme, with the author name in yellow and then white.

The next two: Author above in multicolored font, title below in thin caps, no box, but a story-related icon at the bottom of the spine.

The final two (that I own): Author either above or alongside the title but in very thin, spiky caps; title in white, near-cursive font. No box, icons at the bottom.

It's infuriating! Why would you keep changing the spine design for a series? Not only does it make it harder to pick the books out from a bookstore shelf, but they don't look connected on MY bookshelf. Orion did the same thing with Ian Rankin's Inspector Rebus novels, changing the spine font halfway through the series -- highly annoying when you're collecting all 20. Everyone knows that a row of classic Penguins — be they orange for literature, green for detective fiction, or blue for science — is a thing of beauty
because of its standardization, not despite it.
And don't get me started on the year-long wait for the paperback version of the B&M novels to be released after the hard-back ...