As a first post, here is a quick summary of the Thai books I own and have used in my self-study. (Roughly in order of purchase.)
Teach Yourself Thai (with CDs)- David Smyth
This was what I used to get myself off the ground. In terms of reading, I've outgrown it.
Thai: An Essential Grammar- David Smyth
(I never noticed this was written by the same guy.)
โดราเอมอน (Doraemon) Big Book 3: โ อ๊ะโห... สุดจะซึ้ง (purchased in Thailand)
A Thai manga I bought in Thailand. I can read a good percentage. Even though my vocab is horrible, my grammar is solid enough that I can follow the stories without using reference.
SE-ED's Modern Thai-English Dictionary Mini Edition (purchased in Thailand)
My only problem with this is the lack of pronunciation info.
Thai for Advanced Readers- Benjawan Poomsan Becker
I dug into this prematurely, but it really helped me progress. I've worked through maybe half of it so far.
A Reference Grammar of Thai- Shoichi Iwasaki and Preeya Ingkaphirom
This is very linguistics-orientated (and expensive), but it's by far my favorite resource.