Novels - Word Count and Pages

Reader trends have been changing now more people are reading using e-reader devices. When I first began writing, agents and publishers required a novel with approximately 85,000 words. Unfortunately, what I've found in many books is that the story is padded. Needless information and what is often called data dump gives the reader pages of backstory and history that is unnecessary to enhance the story, but satisfies the publisher (usually not the reader who often skips those pages).
Now many authors are self publishing, they can choose their novel length and word count which is changing from industry standard. Readers are flocking to shorter books that are more than a novella (20,000 to 50,000 words), but less than a novel (50,000 to 110,000 words). Cozy mysteries in particular are more the length of the YA novel (50,000 words or approx. 175 printed pages).
You can read a list of categories and word count here

What are your thoughts on novel length?
Do you prefer to read a story quickly (150-175 pages) or prefer 400+ pages.