I am interested in what people read because it is a decent indicator of both their intellectual development and their priorities in life. And I am interested in figuring out if the reading that people have done has endowed them with additional desirable abilities: creative and independent thought, a wider worldview, more universal explanations, skeptical attitude etc. If one doesn't develop these qualities, one might as well not have read anything. These are qualities which are neither taught in school, nor in real life. Life, in general, is mostly just following orders, unless one chooses to do something about it. And one will be left richer for trying.
I remember the first serious book that I read was A Study in Scarlet by Conan Doyle. It was suggested by a friend of mine who was four years younger than I was (I must have been about 14). I was, therefore, highly impressed by the literary repertoire of that friend considering his age. I ended up buying the complete works of Conan Doyle (Oxford edition) from a bookshop in Nainital where I had gone for a summer vacation with my family. Apart from that book which contains 4 novels and around 50 short stories, I do not remember reading anything seriously till the time I started my undergrad education. During this period my reading mostly comprised of dreary volumes on Math, Physics, and the worst subject of them all, Chemistry. In some sense, however, these books were better than the ones that I came to read during my undergrad. Those four years were spent on the books which I now associate with being on the absolute bottom ladder of literature: sensationalist fiction of the kind that authors like Jefferey Archer, Frederick Forsyth, Sydney Sheldon, and Robin Cook write. These are books which can be safely considered utter trash and should not be brought up in polite conversations among civilized folks. It wasn't until I graduated and moved on that I realized how much there is to know and learn and read.
I think there is a general rule of thumb which applies to a every facet of life, that there is a lot of noise out there. Most people do not know what they are talking about and, therefore, one has to carefully choose whom to listen to. When it comes to books then I have found it extremely helpful to immediately ignore the advice that most people give me on which are the good books out there. Similarly it has been a very good decision of mine to stay clear of Top 100 lists and other such balderdash. I have, however, taken the advice of those whom I consider very intelligent and very well read people, the first one being an old friend of mine whom I have lost touch with, named Basava. Rather than introducing me to specific authors he introduced me to the general possibility that there exists serious and extremely satisfying literature out there. But I suppose the people whom I am most indebted to are some fellow PhD students from UCSD. Aneesh, Kowsik, and Rathina, all of whom, curiously enough, come from the Southern part of India. I learned about Russian, German, French, and Spanish authors from them and developed an interest in philosophy, psychology to some extent, semi-technical science from areas different than mine, politics, economics, chess etc. I had engaging conversations with them which I remember with a lot of fondness now. Apart from the reading suggestions which I received, explicitly or implicitly, from these people I remember only a few other book suggestion which I found interesting (Great House, Infinite Jest ). All other suggestions, I am happy to say, were ignored. Nowadays my contact with these people has been minimized but I have found myself taking the recommendations of those whose brilliance is second to none in this world. Berlin's recommendation of Herzen, Nietzsche's recommendation of Dostoevsky, Krauthammer's recommendation of Berlin and John Stuart Mill, Nabokov's recommendation of Joyce and Dickens etc.