Robbie mentions below how excited he is about reading for pleasure. I couldn't agree more. I was home-schooled through high school, and by the end my education had become extremely informal, consisting largely of my reading whatever books I found interesting at the library. There was perhaps too much fiction on that list but it seems to have worked out okay. I had a lot of time then, in fact nothing but time, for reading.
I've been in college studying books for the last seven years, and if you study books full-time you know how little time that leaves for plain-old-reading. Sure, there's your leisure time, but after a day of reading what someone else chose for you, it becomes, perversely, more difficult to set aside time for something you might actually choose for yourself. I've tried to do better about this in grad school, but it's not easy when you often have several classes that expect you to finish substantial works in a matter of days and come out the other end prepared for deep discussion.
The most frustrating thing about this dynamic is the way that your instructors will often ask, having chosen the bulk of your reading material for the last year, "Have you read Major Book X?" and then look at you like you're a crazy person when you shake your head. The idea that I should not only spend my reading time for class on their favorite books, but then go on to read those books on my own time, seems ludicrous: do they see any value in exploring one's own interests? At what point in the year am I supposed to pursue what I love?
The value of canons is of course the common vocabulary they build among those who share them. This is not to be dismissed as a value for students of creative writing: it's good that we can talk about the works of Flannery O'Connor or Hemingway or whomever when we want to talk about a certain technique. But of course canons are chosen by certain people in certain moments, and too rarely revised or expanded. Most of graduate school's official-unofficial reading list consists of rich or middle-class white men writing moralizing literary realism. If you want to break outside that mold, you can read Barthelme or Saunders. These are your options. If you want to go really experimental, they will suggest Alice Munro, and no, I am not kidding.
Because I do see the value of a canon, I would like to see programs make lists of the books they expect students to read on their own time in addition to those assigned in class. This would be nice because then a) students would know, and b) it would require instructors to scrutinize their own choices and expectations more publicly and explicitly. It's very easy to continue perpetuating our stale canons if we never have to examine them collectively, only mentioning one over-similar author after another. If we were to explicitly make a list, we could be challenged on our choices, our expectations, our values. If we never say what we value, if we simply assume that everyone shares our preferences -- as has been the prerogative of middle- and upper-class whiteness for time immemorial, and as is now, not coincidentally, the prerogative of literary realists -- then we never have to question ourselves.
Personally, when I get done here I plan to read some David Markson. I plan to read some Ursela Le Guin. I plan to read genre again. I plan to read comics. I plan to read the Brian Evenson collection that has been sitting on my second couch, neglected, since AWP. I plan to have some fun, which is a value too many writers forget in their reading, and ultimately their writing.