StorageReview reviews storage (and it is good)
Far and away the web's best resource on hard drives, StorageReview has been a favorite of mine for years. They're back again this summer with their yearly drive roundups, and 7200rpm ATA drives are up first. With 15GB per platter and, at least in some cases, virtually silent operation, these drives are too sweet to ignore.
Read the review, then spend some time plunking around in the nifty-neeto SR database. If you're not afraid of obsolescence, you could compare one of these new drives to whatever you're using now. Or, for fun, compare 'em to a little bit older SCSI drive that's still twice their price, then use the scores to torment the resident SCSI snob.