I recommend reading How To Read A Book by Adler and Van Doren. In it they describe a process for quickly analyzing a book and deciding whether to read it in detail - and if you do - how to get the most out of the information presented.
With this technique you can better decide what to read and when to commit to reading.
If you are browsing books at a bookstore (or flipping pages in the online preview) you can also look for what actions the author is suggesting. Little or no "actionable content" is probably good enough reason to put the book back on the shelf. Far too many books these days just string together stories, or present a lot of theory, and in the end fail to describe how to solve the problem that the author has proposed.
I would recommend audiobooks, listen to them whilst you drive and when you are doing non work related activities. If the information is relevant it will be pretty obvious quickly if something is worth taking note of.
For business books, I recommend reading book summaries, as most books have a few good ideas and add several hundred pages in order to sell better. People apparently want to feel they are getting good value by wasting more time and killing more trees.
You can even get summaries in audio form so that you can listen while you drive or even swim. I have a water-resistant mp3 player for this reason. :)