Borrow or Buy

I've been thinking lately about borrowing books from the library versus buying my own copies. Its alot cheaper to borrow them, especially if you're not sure you're going to like the book or not. But there are time when I've read a really good book that I had on loan and ended up wishing I'd bought it. Perfect example, THE KITE RUNNER. I'm now on a mission to find a good used copy of that one. My aunt told me about a website called Alibris that sells used books. Its a great site and even though I personally haven't bought from them, my aunt has and she has been pleased so far. But that brings up another dilemma: when buying a book do I just buy the softcover or splurge and get the hardcover? I actually prefer the softcover version (the over-sized paperback) because they are easier to handle and they fit in my purse if I want to tote it with me. However, the hardbacks look so nice on my book shelf. I know it shouldn't matter, but little things like that bother me. Anyone else have any thoughts about this?