Part of the difficulty in properly answering your question is that it in turn depends on what your orientation is.
For example, I personally have not found Jungian-type oriented books very useful when it comes to better understanding the symbology of cards - though many others seem to actually prefer such orientation.
Likewise, if a book principally addresses the images and their meaning from a Golden Dawn perspective, I find this tells me more about the GD than about Tarot. But of course, for those who have such preference, then the descriptions are quite meaningfull.
It would probably help, for more 'targetted' suggestions, to have an idea as to what you may prefer.
As a general suggestion, I have yet to find a book comparable to R. O'Neill's Tarot Symbolism. Until it gets reprinted next year, however, it is very difficult to find.