I've got a 12" 1.33Ghz G4 with 1.5GB of RAM and a 4200rpm 60GB hard drive. I've noticed that it's not as speedy as it used to be. The only thing I can upgrade is the hard drive. Now, my question is this. Will I notice a significant speed increase if I upgrade to either a 5400rpm or 7200rpm drive or is the upgrade insignificant enough that I should just look to continue saving for a Macbook?