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If you're looking for a sweet 12", I have to go with the herd and advise the 12" Powerbook. This thing is the perfect portable for school.

+1
I just bought a new battery for mine (NuPower) and it lasts for ~4.5 hrs. It weighs 4.6 lbs, which can be a downer at times, but that's not too bad.
 
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