I skipped over the comments so pardon me if I'm echoing things that have already been said.
I would also absolutely buy the book.
What's great about blogs is their immediacy. "Sale at Nordstrom--go!" "Here's this great boot that just came out for people with smaller calves." Etc. Everything is up to the minute. You don't have that advantage with a book.
A book's strength is in its organization and focused, condensed dissemination of information.
The difficulty of using a blog, especially one that's got loads of archived posts, is simply that even with a search engine, the information is scattered everywhere. If I want to know whether and how someone petite can pull off wearing ballet flats, I can punch in those terms, and if I'm lucky, something will come up, and probably it will. But it will be a meandering search at best.
Admittedly, I haven't read too many fashion blogs. Or read that many fashion books. (The ones I have read, and own, are The Pocket Stylist, The Lucky Shopping Manual, Brenda Kinsel's Fashion Makeover, How to Have Style by Isaac Mizrahi and Ready 2 Dress, which I think was the prototype for Susannah and Trinny's original TV show. They all have their different strengths.)
Blogs and books are like apples and oranges, but what I feel is this blog's and Angie's strength (beyond the dialogue between us and Angie, which can't happen in a book, obviously), is her completely thorough understanding of basic style principles overall as well as for different body types, not to mention her own completely wonderful personal style, and respect for others' personal vision for their style. Of course with her background as a buyer and thorough knowledge of sourcing things, she is a shopping expert too, and maybe to a degree some of that wouldn't get dated even in a book (though boutiques and companies do go under).
As I am writing the above, the thought came to me: wouldn't it be fun to read a book which followed a personal stylist and a few of her clients through the process of finding their own style and dealing with their unique challenges? Maybe as one or two chapters in an overall manual.
Incidentally, one thing that always frustrates me with these other books is they'll give an example of what to do if you're short...or plus-sized...or top-heavy...Well, what if you're ALL of those? LOL, but in a way it's not funny!
Oh well, I'm a writer and wannabe editor, but these are just a few thoughts. It's amazing how many people I've seen (this is in the food blogging world, but I'm sure it could carry over into other areas) who started as unknowns with blogs and ended up with publishing deals. Angie would absolutely be considered qualified.
Oh, I wanted to add that photos, photos, photos are really important. I do like The Pocket Stylist a lot but it suffers from not enough visual explanations of a lot of terms that are not obvious to me. I can go and look them up online, but it slows down the whole process.
Well, enough rambling...and if Angie does write a book, I can say that she will be disappearing from here for a while (books are huge undertakings), but it would be a fantastic compendium and resource for anyone who wants to elevate their style. But if she's happy with her current baby (YLF), that's awesome too!