High Yield should give you 80-90% of molecular biology however it isn't complete because it doesn't talk about differentiation of vertebral limbs of fibroblast growth factor, Sonic HedgeHog, or HOX genes. You will see questions about these esoteric topics on the USMLE. BigFrank mentioned that the there is a greater emphasis from biochemistry to molecular biology. He is partially right. The real renaissance is in embryology. The new questions about HOX, PAX, and vertebra differentiation are in the arena of embryology (not molecular biology!). The tough questions that people are talking about are in developmental biology.
I prefer developmental biology by Gilbert. It is much more current (2003 rather than 1999) and it comes with a CD. Plus, it talks about HOX and Sonic Hedgehog in terms of differentiation. The book is dense but I use it for reference only, besides it is a good embryology and molecular biology review too.
Reading Lodish or Alberts as a reference is not a good idea. It barely touches the surface on HOX genes. That's because those books have a broad scope of molecular biology and is used as references by Graduate Students. Developmental Biology is more medically relevant. Check the book inside at Amazon.
http://www.amazon.com/exec/obidos/t...102-2769336-7470567?v=glance&s=books&n=507846
If your goal is less than 240. Completely disregard my post and memorize High Yield Molecular Biology.