Worst hard drives ever, Maxtor Slims. My work sold them in a lot of computers about a 2 years ago I think, and they are all coming back now with dead hard drives.
I had a Western Digital Caviar, but it crapped out on me after about 6 months. I got a Seagate Barracuda, and it's been awesome so far. Then again, I now have a Raptor, and it's great.