Some products become the mainstream because of a trend (e.g. iPod). Others become the mainstream because they simply kick the **** out of the competition (MP3 Players in general).

HD MP3 Players have much higher capacities than 1GB. If you only want 1GB you want to get a flash MP3 Player. Personally, I would never consider a player that can only hold ten or twenty albums. At least the mini HD MP3 players have 5 or 6 GB.