If I may share some of my experience on the matter:
I was pretty dismal at school due to a myriad of reasons, and as a result I was presented with a big, fat E for my GCSE Maths. 9 years on I decided to resit, and taught my self using a combination of revision books and GCSE Bitesize. I have now purchased the CGP AS-Level Mathematics book. My process is to use the revision books as guides to what to learn, in addition to being used as actual learning material. These are supplemented by information on-line, in case the information is being provided in an obtuse way within the revision book.
Personally, I found Kahn Academy counter-intuitive for me, although it's clearly a great resource; i preferred sticking to the official syllabus of the various exam boards in the UK, and I found that Kahn Academy just confused my procedural method of learning. Something...whatever. Anyway, revision books as an insight into what to learn supplemented by internet sites (Such as Kahn), but NOT using Kahn as a checklist of what to learn. That's my method, and it seems to work.