I am also preparing for level 2.
While preparing for level 1, I spend loads of hours in the web searching for books and online material. I ended up purchasing two LPI books, some general and some specific.
Now, that I am preparing for level 2, I analyzed the method I used for studying level 1.
- I won't buy any book.
- I like printed material as well, but I don't think it is a big advantage. You are in front of your monitor anyway.
- I don't want to read a lot and try to put it into practice hours later. I read a paragraph and hack the config file a few minutes later. Practice is all you need.
- I am studying according to the LPI objectives. I take one subtopic and study the description and key files until I know how to define the objective myself without reading it.
- I take a quick google search (tutorials and/or howtos) selecting 2 or three sites. I study them in order to select the best of it. If there is a lot of text, I print it out.
- I study the tutorial putting my hands on the keyboard whenever it is possible.
- I repeat the task as long as I would probably be able to write a HOWTO myself.
- I check the second selected web site to see if I missed some aspects.
- I check the knowledge I just gained against the description and key terms.
- I am done. Here I go eith the next subtopic.
So, IMHO you don't need a book. It is, however, nice to have it on the shelf.
The snow.nl site is good, but it is not the best in all aspects. I you study by subtopics you can print out the HTML pages of the snow site. There is one page per subtopic.