I've got to admit I use PowerPoint, and I like it. I would say that I am an advanced-level user. As a way to improve my own PowerPoint skills I have ordered some books to help me get better at it, and in glancing over the books I am pretty impressed with what I see. As I digest the books I will give you more details. The books are:
(1) Better Than Bullet Points: Creating Engaging e-Learning with PowerPoint
(2) 7-Slide Solution: Telling Your Business Story In 7 Slides or Less
(3) slide:ology: The Art and Science of Creating Great Presentations