get this or the caviar balckhttp://www.newegg.ca/Product/Product.aspx?Item=N82E16822148840
either one wont do you wrong. the momentus is a laptop drive.
the momentus xt is a hybrid drive. yu do get some increase in speed, but it only has its advantage if you do the same tasks frequently. if you are to get the hybrid, get the 750gb version. it has more nand.