Hard drives are mechanical devices manufactured to strict tolerances, and though I wouldn't say failure is common for new drives, it does happen.

In the case of the TouchSmart, you were probably bitten by the Seagate firmware bug that affected many people. Issues of this magnitude are are also extremely rare. I still have confidence in Seagate drives, because at the end of the day all drive makers have had a few issues over the years. For example, Hitachi's DeskStar 75GXP and similar models became known as Deathstars. Even though they were technically made by IBM, it was very bad for Hitachi's brand at the time.