Wow. What you went through is exactly the same as my experiences. I bought a macbook(black,core duo,2G RAM, 160G HDD) in late November, and one month later, the hard drive totally failed. It did not just start (mount) on one morning. Apple replaced the hard disk.

Then 6 weeks later, the hard drive again failed! All the programs froze suddenly, then I could not reboot the computer any more. It just kept on making some cluttering noise. Apple is now replacing the hard drive. I asked them to give me a new computer rather than keep on replacing the hard drive, but the request is refused.

I am a regular computer user and I never abused or dropped the laptop. I wonder what has been causing this rather unusual problem. What if this happened the 3rd time? I have been asking the Apple.