Either one would be good, depending on what you're looking for.
Chris Hart's book will teach you a bit on how to draw characters for animation -- handy if you're not comfortable with your 2D skills. It's not really an animation how-to book but more of a general overview of the processes. It has a focus on character design and construction and is definitely geared towards 2D animation.
Timing for Animation -- which is by John Halas and Harold Whitaker, not John Lasseter who only wrote the foreword -- is a good general reference book for, well, animation timing. There's info in the book on how many frames it takes to get a good explosion, how to do splashing water, breakdowns of walk sequences, etc. It's fairly technical, in terms of traditional animation, but it's still good information. This is also a very 2D-oriented book, but the fundamental concepts can still apply to 3D.
I own all three of the books, and I usually look at them in this order:
Animator's Survival Kit
Timing for Animation
I haven't looked at Chris Hart's book in months. The Animator's Survival Kit pretty much provides all the information that I need. Occassionally, I'll open up Timing for Animation, but that's only for my animation classes.
Hope this helps!