I read a lot of books - relatively speaking, I mean. I'm a slow reader, because I take in every word and can often recall entire passages. Sadly, my son has inherited my pace, which makes getting through all his Advanced Lit reading in high school a bit painful. My daughter has no such problems. In fifth grade, she cranks through books, having inherited this ability from her mom. She'd read every Harry Potter book on her own by the age of nine. She finished Deathly Hallows in less time than it took me.
So reading is an investment for me. Between working, writing, the occasional TV show, sports, family, etc., a book has to engage me fairly quickly. It has to make me want to know what's going to happen early on. This may be one of the reasons I read a lot of YA nowadays, apart from the fact that it's also what I write. These books often grab right away.
Some of my favorite recent non-YA books were either "immediate grabbers" or offered up familiar characters. Sandman Slim -- not exactly YA -- is a great example of the former. This book grabbed me by my earlobes and dragged me along. The Lost Symbol is a solid example of the latter. Robert Langdon is a braniac/everyman sort of hero.
And then we have the books that I grab with every intention of reading cover to cover, but for one reason or another, I bail. The worst example is a high fantasy novel I picked up at the local library a couple years ago. Honestly, I don't remember what it was called. At the time I was reading a lot of high fantasy because, technically, I was writing high fantasy. (That's debatable, but it's where my story landed). The book seemed interesting enough - it took place in a completely fictional world, and I fully expected to be immersed in a whole mess of world building.
I made it through two chapters before I returned it to the library.
It was here I discovered my lack of passion for "true" high fantasy. Lord of the Rings is the primary exception, but generally I need a little grounding in "our world". I want to experience the journey into fantasy with the characters. If I'm going to invest in learning all the intricacies of an entirely new world, then I need to like the characters a whole lot. I didn't like them. Not soon enough anyway. And so I didn't experience the fantasy because I'd checked out.
Then we have Stephen King. I love his collected works. But it's kind of like Bruce Springsteen and Billy Joel in that, as many of their fans have said over the years, "I prefer their old stuff." The man writes tomes. Going back to The Stand, It, The Talisman (my 3 favs) - these are long and I adore them. His later work is a bit more literary, which is cool and I quite liked Duma Key and the Girl Who Loved Tom Gordon. One of his most well-received books of a few years ago -- Lisey's Story -- is still sitting on my night stand. I'm a little less than halfway through it. It's good, but it's kind of my rebound date. When I don't have another book to read, I go back to it and read some more. But it doesn't hold me like the others do. I suppose if I spend enough time with it, we'll go all the way.
Oh, and I can't wait to read The Dome.
My final example is Douglas Coupland's, Generation X: Tales for an Accelerated Culture. I couldn't put down his book, Microserfs. It's really one of my all time favorite novels, because of the characters and the setting (I'm a techie, geek writer, after all). Since I'm a gen-X'er, I decided I had to read this book, and so I began. I read about fifty pages before putting it down for good. Up until that point, it was three characters telling a variety of little stories, while revealing bits of character detail and back-story. It didn't grab me and was taking me too long to get through. It just wasn't for me. I've become crotchety and impatient.
I feel bad when I put a book down for good (or cheat on one book with another, only to return later, tail between legs). Do I give everything a fair shake? Yeah, I think I do. Fifty pages, minimum. All bets are off after fifty pages, though.