so my new blackbook has been ordered! turns out, though, since it was a birthday gift and i'm not the one ordering it, that it was ordered with the 250 gb hard drive. it is 5400rpm, but i'm wondering if it's slow compared to the other hard drives. see, the thing is, i only have 17 gb of data (music and pictures mostly)...i don't need that much space! so is there any reason i should get the other hard drive...maybe because the smaller one is faster? also, since i don't need that much space, would it be worth it to buy a smaller 7200rpm hard drive and swap them out? (for example, the hitachi 7k200, etc.) will i really notice a difference? what do you think i should do?