If you're gonna use it for school, get an ipad. The awesome battery life'll let you stay at the library longer without worrying about a charger and if you pair it up with a bluetooth keyboard, you'll be able to carry 3.5 lbs less when you go to the library.
I actually just used it for studying and its friggin' awesome!! I sat myself down at the library, spent 7 hours making a study guide, and converted the document into a PDF file, and used the ipad to study it everywhere i went 😀.
If you already have a 2006 MacBook, you don't need another.. The current specs upgrade aren't that impressive. If you want a speedier MacBook, i highly recommend upgrading to intel g2 ssd... That upgrade is definitely a lot more noticeable than a CPU upgrade.