I have a 2006 CD MacBook and I'm thinking of upgrading to the 2008 Unibody Aluminum MacBook. Are there anything I need to watch out for or look for? Any kind of defects or anything to be aware of? I'd like the 2.4GHz version with backlit keyboard (I think that's how they come). I'd also like to spend less than $400. It's not a necessity, but just have a desire right now and if I can find a good deal I'll take it. My current MacBook keeps me happy.