A dictionary makes a great Christmas present - I think so, anyway. Most households have at least one dictionary, and they do get out of date quite quickly these days. Collins published a new, 30th anniversary, edition of their dictionary in 2009, and there was an updated Concise Oxford Dictionary published this year too. They're both excellent dictionaries.
I like Chambers dictionary, too, as it has lots more words in it than the two mentioned above, particularly Northern English and Scottish dialect words. It's rather quirky and is renowned for its humorous definitions eg Mullet: a hairstyle that is short at the front, long at the back and ridiculous all round. It has words in it which I could never imagine anyone ever needing or wanting to use eg paneity (the state of being bread) and shunamitism (rejuvenation of an old man by a young woman). Shunamitism the word might never be used, but of course the phenomenon still exists - the names Ronnie Wood and Rod Stewart spring to mind! I blogged on the 2008 edition of Chambers here.
For anyone thinking of buying a dictionary as a present, here's a blog I wrote last December giving hints on how to choose the best one for your purposes.