I am planning to buy a new 15" Powerbook. I have some questions about what options I should choose: 1) How much difference in speed will I notice if I upgrade to 1 gig of RAM instead of 512 MB? I don't plan on getting the extra RAM from Apple, but I need to decide if I should pay the extra money to get 1 SO-DIMM of 512 instead of 2 SO-DIMMs of 256. 2) How much difference in speed will I notice between a 4200 RPM hard drive and a 5400? 3) Is AppleCare worth it? What are the chances that it will break and if it does how much will it cost to repair? Also, I will be ordering through the education store and I've heard that you get free extended AppleCare. Anyone know about this? 4) Will they do BTO options such as a different optical drive or extra Video RAM at an Apple retail store or do I have to order online for that?