I desperatley need to replace my macbooks hd with something bigger. I've been pricing 200-250g hd's from apple for about $230 US. I've noticed others such as this one http://www.newegg.com/Product/Product.aspx?Item=N82E16822145160 for considerably less. Any reason that model wont work? What should i be looking for when purchasing a hd? And I'm currently running 5400 rpm, what will the 7200 rpm upgrade do performance-wise?