I seem to have the worst luck. I'm writing this on my third Macbook Pro replacement, and this one (2.8ghz 15" 4gb) seems to be the worst of all. Why? Less than two weeks after receiving it, the left fan started making a rattling noise. We're not talking about a once in a while thing---it sounds like there's a card in the spokes of this thing. I thought it might go away if I ran the fans for a while, but it only got worse. I called Apple and was told that I was just a hair outside of the thirty day replacement guarantee, so I'd have to bring it in for repair AGAIN. That's not the only issue---starting three or four days ago the computer would just freeze in the middle of something or nothing. I could be on digg or stickam, or listening to music, or just recovering from one of the freezes and it would freeze again. The mouse wouldn't move, screen wouldn't change. I couldn't make any input changes to it. Sounds like hardware to me. Going with that train of thought, I popped in my OSX install disk and tried to run a hardware test. I hold D and it boots up to what almost looks like a DOS prompt, but isn't. Kind of like a black screen with an underscore in the top left corner. I left it there for about 5 minutes and nothing happened. I tried again and again and again. I also tried tapping F2 at the start up sound and nothing happened there either. I'm at a loss. So now I have to bring in my Macbook Pro that I use every day for work, and possibly lose it for 6-8 days AGAIN (for the sixth time?). I've always heard and thought that Apple had GREAT hardware as well as software, but I'm really beginning to wonder if that's true.