I liked Running Linux, Learning Java, the Camel Book (Perl), Programming Python and 'Python Standard Library'. I haven't finished the Python books yet, but Programming Python is a good book, but it's very big (> 1300 pages!).
Some O'Reilly books that I've seen are like what Mark described. I usually go to the university bookstore and flip through the O'Reilly zoo they have there before buying one of their books.
