Favorite/Best Korean Cook Book
I think it depends a bit on what you're looking for/how familiar you are with Korean foods. For me, "Korean Cuisine" by Young Sook Choi was a great one to start with because the recipes are simple, straightforward, and there are pictures of key ingredients. It's not a comprehensive book but a good intro to Korean food and I've given copies of it as gifts to several friends. I still cook from it fairly often (I've been cooking Chinese, Thai, and Indian food for years but only began dining-out and cooking-in Korean when we brought our first son home from Korea 5 years ago).
"Growing Up in a Korean Kitchen" is a great read but I've only made a couple of things from it. Someday when I have more time I would like to explore more of the recipes. I remember reading a review somewhere that said it was focused on the more complex dishes of palace cuisine.
"Discovering Korean Cuisine: Recipes from the Best Korean Restaurants in Los Angeles" is a fun read too and has beautiful pictures. I've made a couple of the recipes from that book, too.
The book that I'm cooking from the most these days is "A Korean Mother's Cooking notes," by Chang Sun-Young. I picked up a copy on my last trip to Seoul (it's been revised, but since it seemed like the second edition contained all the same recipes I went for the first edition) but you can get it from Amazon:
I second (third?) the recs for hannaone and Maangchi's site, as well as Aeri's kitchen. Aeri put an ebook together of her recipes, you can download it from several ebook retailers:
this is not an answer to your question, because i don't have any korean cookbooks, but two GREAT resources are hanna one here on chowhound and maangchi on the net.
hanna one has tons of recipes here, and maangchi has videos and a site where you can see the finished dish, along with recipes. she just won a youtube award. http://www.maangchi.com/
maangchi is a sweetie-pie, and she deserves the award.