Back in the 2E days, I got a Monsterous Compendium (the hardbound monster book) that had about 30 pages repeated. No missing pages, just an extra 30 pages repeated in it (starting at Beholder midway through the giants). Oddly, I didn't discover this oddity until after 2E's days were over, so I never was able to return it - but until I realized what was happening in that book, I always hated trying to find monsters in that thing ("Where the heck are the dinosaurs? This skips right from Catoblepas to Firbolg..." *closes book and reopens* "I mean, look here - Catoblepas ... Dinosaur - wait a minute, they weren't there a minute ago...")
In 3E, I got a bad copy of Libris Mortis from a Books-a-Million; the interior of the book literally fell out from the covers after only having it a few hours. I was able to trade it back in with no fuss or muss.
In 4E, my group had bad luck with the books.
My copy of the DMG has red smears through several pages and I've pulled my hand away from the MM a couple of times to find black letters copied onto my fingertips. (I did not attempt to return the books however). After that incident, I just used my PDF copies and the books have sat on the shelves relatively untouched.
One of my other gamers went through 3 PHB in as many weeks; on the first, the binding fell apart in the middle of the game, scattering pages everywhere. On the second, about 1/2 inch of the outside page had gotten cropped (at an angle) off. On the third, the ink smudged on several of the pages (still readable, but noticeable). Sadly, he was one of my players who was the most hyped about the new 4E, and these issues really lessened his enjoyment of the game.
Lastly, the copy of
Keep on the Shadowfell I borrowed from my other player to run our first game didn't escape problems either. After my first read-through of it, I closed the booklet to find my hand peeling away from the cover, taking a lot of the ink with it and leaving a (un)lovely handprint on the cover. That was extremely embarrassing considering how careful I try to be and how wary I am with others handling my own stuff

.