How do you chose books?

So, I've been listening to Stephen King's The Gunslinger in my car this week. I read it years and years ago. I read through the fourth in the series when I was in high school. I think before I was even 16, which is when I started at the library.

What I was thinking today was that this book is not like anything that I every can imagine picking for myself. How did I chose this book all of those years ago, before I had met anyone who had read the series? I imagine that I went into the used book store and pulled it off the shelf because it didn't sound like the usual SK book.

Still, how do you pick a book? I have my list. I started my list during my senior English class. I took a list of suggested reading for a book report and wrote it down. I added books to it at work because I realized that I couldn't check out every book that sounded good. Then I found lists online and added them. Best modern literature. YA's dealing with tough stuff. Now I read reviews constantly for work and listen to NPR. I will never run out of books to read. Then there are the random ones I see at work. One of my next books is called Drizzle and I picked it because the cover was wonderfully bright and pretty. Then there are those authors who I usually feel are just going to be good: Nick Hornby, Francesca Lia Block, Stephen King, etc.

How do you pick books?