Ok, I'll try to answer all the questions...lol
First of all, no matter what the book, I admit, I judge books by their covers :teehee: In order for me to even pick up a book to glance at it, it must have an appealing, intriguing cover.
Also, when browsing books, I like to see designs that are really different. Honestly, the majority of patterns I have seen, I'm not thrilled with. Don't get me wrong, the work is beautiful, but, most of what I see is really not my taste. I guess that's another reason I pretty much don't knit for myself. I dunno, I think I have kind of weird tastes though :teehee:
What would make the book least useful to me is seeing it filled with actual knitting instructions. I realize that in some cases, certain instructions may be necessary, but, I believe that's what the instructional books are for. I mean if a person doesn't know how to knit too well I think they should start off with an instructional book. If there's a certain type of stitch or BO or something for a particular pattern/s that isn't necessarily common, then including the instructions are useful, but, instructions for a basic knit or purl stitch and bind off, things like that, I find unnecessary.
I'm not really sure what most knitting books lack as I don't have a huge collection of them...lol...I have the Stitch N Bitch and Stitch N Bitch Nation books, the Domiknitrix book, the Anti-craft book, and the Naughty Needles book.
As for what makes a knitting book ideal to me is the uniqueness of the designs, and, a variety of patterns for different levels of knitting. I like to see a few different patterns ranging from beginner to advanced.
My favorite knitting books that make me want to add to my WIP's have fun and funky designs, such as the Domiknitrix and Naughty Needles books.
I prefer printed versions of books. I like being able to have a book to take with me wherever I go, and the ease of having a book on hand. Also, I think spiral binding would be best for knitting books with patterns. I hate it when I'm trying to follow a pattern from a book and I have to weigh down the page because the previous page keeps wanting to flip down...lol...Definitely spiral binding!
Hope that helps!