If we're mentioning gifts we gave other people, we will be here for a while, this was a cookbook heavy gift giving year for me.
Most successful was a collection of 'healthy' cookbooks for my mother, who is on a low-sodium diet. I recruited my housemates and my dad and we all worked through a pile of books at the local Barnes and Noble to whittle it down to books that had nutritional information, mostly dishes under 500mg of sodium per serving, and looked like they would be reasonable edible. (Some of the books look like someone started with a chicken breast and threw the kitchen sink on it as long as the sink was unsalted, the flavor combinations were just weird in bad ways.) We haven't cooked from any of them yet because of holiday-related meals and leftovers, but as soon as she opened them my mom kept getting distracted from the rest of the present opening by wanting to read through her new books, which is usually a good sign.
I also gave a few personal interest type cookbooks (one of the Splendid Table ones for my dad, who often listens to the show even though he isn't much of a cook, and a Scandinavian one for my mom that she is reading for interest as much as for recipes, for example) and then my other big cookbook gift was a copy of the Cook's Illustrated Meat book, which I selected after consultation with folks here to make sure I was reviewing a good selection of meat related content. The recipient is my housemate who is a 'recovered' vegetarian - raised vegetarian, started eating meat as an adult - and as such likes meat but has no idea how to select/store/cook/serve it. There are a number of meat specific cookbooks (I spent far longer than I should have reading the River Cottage one even after I'd ruled it out as a gift) but the CI one seemed the right tone and approach. So we will see what happens next time he decides to cook for the house. (His son ended up buying him an America's Tesf Kitchen book too - What Good Cooks Know - which I suspect is far too entry level for most eGullet folks but does look right in line with what a relative kitchen newbie needs to understand to get the best results in the kitchen.)
ETA - can't get Amazon link to work from my iPad for some reason.