What it call comes down to is this -- should you invest your time and attention in reading the book behind the hype? Absolutely.
The first section (A Deeply Religious Non-Believer) serves as a good introduction to what Dawkins intends to cover. However, unless you're a hardcore atheist looking for solid debate material, you can safely skip sections 2 and 3 (The God Hypothesis & Arguments for God's Existence). I found them to be dry, tedious, and often over my head - not so much because I couldn't follow then, but because I couldn't be bothered. It's as if Dawkins dedicated these 2 sections to convincing his fellow scientists that his book has merit and that it should be studied. Skim away and you'll miss nothing.
Section 4 (Why There Almost Certainly Is No God) gets things back on track with some serious discussion about natural selection. The distinction between random chance or luck versus natural selection is very well laid out and throughly engrossing.
It's sections 5 and 6 (The Roots of Religion & The Roots of Morality) that should be mandatory reading for anybody with the slightest interest in the philosophies behind faith and atheism. Section 7 (The Good Book And The Changing Moral Zeitgeist) is one of the most fascinating things I've ever read. Dawkins will probably be accused of picking and choosing to illustrate the most heinious acts of the the Bible, but (as he points out) that's exactly what the church does - they pick and choose the good bits, the nice bits, the bits that support their faith. The rest? It just gets swept under the rug.
The next 2 sections (What's Wrong With Religion & Childhood, Abuse, And The Escape From Religion) are certainly the most controversial portion of the book, but Dawkin deserves full credit for not shying away from the uglier side of religion. Much of what's discussed here should be obvious, but that's the whole point - for most people, it's not.
Sadly, the final section (A Much Needed Gap) serves as weak wrap-up, and a huge dissapointment after the true meat of the book.
It needs to be said that Darwin is not, as his critics have claimed, simply a bible basher and tyrant against religion. He identifies and recognizes the perceived need some people have for their faith, and doesn't ridicule them for it. Several times in the book he holds up one religious personage or another as being worth of respect and esteem for their actions. This is not a book of hate, or one written out of spite. You may not agree with it, you may not like it, but it should make you think.
Of course, if you're not interested in thinking . . . if faith is the be-all and end-all . . . then the true value of the book will be lost on you. The world is a wonderful, curious, delightful place that works in fascinating ways. Shrugging off those wonders, or crediting them to some imaginary deity, just cheapens the world around us.