I\'ll always recommend Samsung, especially over WD. I got a WD 500 gb disk because it was available locally and I needed a disk fast, but I\'m a bit disappointed with it. It\'s not nearly as quiet as my old 200 gb Samsung... When I get another disk, it\'ll be a Samsung for sure. Fast, quiet and reliable.
It\'s been a while since I had Seagate, so I don\'t know how they fare nowadays. I\'m sure they\'re ok (didn\'t they buy WD though?).