I've always enjoyed doing pencil puzzles now and then, but in early 2007 I became a bigger fan after finding out about the great variety of relatively simple puzzles the Japanese company Nikoli publishes. Most of the puzzle books I own are by Nikoli, ordered directly from them in Japan. I do have a few other books as well, but got ones that contain many of the same types of puzzles as Nikoli's books. After the list of books I own is a list of some books I'd like to get and sometimes some notes on why.
Unless otherwise stated, these are published by Nikoli.
These are generally ordered by preference. The Puzzle Box books are my favorite right now, with Penpa Mix close behind. The Puzzle Communication Nikoli books are good, but have too many puzzles I can't solve because they're word puzzles or English rules are unavailable.
If you're looking for gift ideas for me, these are a good idea if you can find the books (or similar ones) in the US or are willing to order from Japan. If you're interested in talking about puzzles or helping me learn the rules of Nikoli puzzles, feel free to write to me at dronak [at] yahoo [dot] com and we'll talk. I could definitely use some help making sure I understand the rules of games for which I can't find any English descriptions. Thanks very much!