I agree with PDE (if I can agree, it more seems like what he's saying is fact). I haven't had as many computer as him though, only three MacBooks and one MacBook Pro, and all have been defective. I'm going to get a new MacBook Pro soon, hopefully issue free, but honestly, I don't expect it.
Same thing. Two macbooks. One had to be sent in for a replacement, the new one came in with a bad backlight buzz (but my dad cant hear the inverter so i am not sending it in). The other macbook had the buzz from the magsafe. I tried to get apple to fix it but they said I had to bring it to an Apple store (6 hours away) otherwise, if their engineer didn't hear the problem I would be charged. That was insane, my isight camera records the sound and i can play it back.
If it wasn't for OSX I wouldn't buy an Apple.