I am planning to buy a Macbook for school use and the only thing I am concerned about is its graphics card. I will be using it for word documents, the internet, and watching DVDs. I don't plan on playing many games or a lot of photo editing. Later, I may decide to run Windows Vista on it. How good/bad is the graphics card on a Macbook and can it handle Windows Vista? Also, do you think that refurbished machines are very reliable? Thanks!