I think Apple really needs to back off this thing with restricting access. My sister's Toshiba laptop makes it easier to switch the hard drive than Apple makes it to switch RAM. Changing a hard drive on her computer -- which, by the way, is about a 6.5 pound, 14.1 inch model and about four or five years old -- is based on the same principle as changing RAM on the Powerbook, only with fewer screws. You just open a hatch and pop out the hard drive, and pop in a new one.
I think it is especially important to make the hard drive accessible because it is probably the single most likely component to fail and making it a user-changeable part is an incredible convenience; letting you do in 10 minutes (plus, say, an hour and a half's worth of software installation) what you would have to wait three or four business days for the service tech to deal with. Bottom line, for me it is the difference between being able to use a laptop as your only computer, and not being able to. I can't afford four days of downtime. I'm fortunate in this respect in having a Digital Audio G4 that is super reliable and super easy to repair. When I kept blowing through hard drives on this machine when I first got it (due to Apple's phase of supplying incompetently refurbished IBM and Maxtor replacements that were the subjects of class action lawsuits), it was at least quick and easy to solve the problem.