I have enough money saved to buy a 12" or 15" Powerbook for college in the fall -- starts in August -- but am unsure if I should purchase one now or closer to the start of school. I have used IBM-compatible PC's for most of my life, but am ready to switch (I have some nightmare stories about Windows). I am pretty familar with computers, but will need some time to get used to a new OS. Plus, I've never had a computer of my own - will a Mac take some getting used to? Buy now or later on?