I will be purchasing a macbook in the near future and have a problem deciding between three different hard drive configurations. The standard hd is the 120gb @ 5400 rpm. I will automatically upgrade to the 160gb @ 5400 rpm. I am wondering whether I should keep upgrading and go to the 200gb @ 4200 rpm for an additional $100 or the 160gb @ 7200 rpm for an additional $150. Is the 200gb that much slower than the 160gb @ 5400 rpm and is the 160gb @ 7200 rpm that much faster than the other two?