I would definitely go for the You Speak Korean series by ParadigmBusters for self-study. I have their first 3 volumes (waiting for the forth) and I also have Ross King's Elementary Korean and Intermediate Korean books. The one caveat about the ParadigmBusters books: no CDs, but you can download mp3 files for many of their dialogues. I also think the Sogang series is very good--plenty of audio there, but not quite as amenable to self-study. Actually, both the ParadigmBusters series and the Sogang series would work well together, depending on your budget.
I like both of Ross King's books, but I really think they're best used as part of a class or as additional resources for books like those from ParadigmBusters and Sogang. I don't think they'd be ideal as primary, self-study texts. But it's pretty easy to look up grammar forms in Elementary Korean and Intermediate Korean and I mainly use them for that purpose.
My feeling on these types of questions, about which book to use, is that I had to go through scores of books for the same level, because there was just so much material per level, too much for one book ... you can't go wrong, because you're still going to be at the same level after finishing one of them.
But, you are using this koreanclass101.com for listening, yes? it's really great for developing your listening. If you want to study additionally, then start poring over books of which there is no shortage these days .....
I know many of you use KoreanClass101.com for listening but, KoreanClass101.com's materials will get better; especially, new series that are coming soon in July will prove my point. My methodology and lesson notes are unique and easy comprehensive.
Yes, finding good Korean books is important but, most books are same.
Listen and check out the new series lessons: Absolute Beginner Season 2 and Audio Blog Season 5.
I do really work on my lesson notes and materials. Absolute Beginner Season 2 would be really helpful for Korean beginners. I bet it!
Using Korean is very good for advanced speakers, they deal with a lot of grammar and stuff.
But maybe it's a not book for beginners.
You may try Sogang University Korean course.
it's free, they have videos grammar recordings everything.