Manual vs. Selected Playlists
I used to be manual-only, but I've finally (5 years later) been won over to "the iTunes way".
I have less and less time to listen to music, and one way I've been making up the time is to spend less and less time managing my music.
Instead of painstakingly tweaking the contents of my iPod, I painstakingly tweaked my playlists, smart playlists, smart playlists that depended on other playlists, etc etc.
Now instead of spending any time when I plug in my iPod, I spent a lot of time once, and now everything auto-magically gets updated, with different songs I don't hate and anything new and important. It's especially handy for keeping a Nano or Shuffle from getting stale (without giving up ALL control).
I'm always suspicious at first of Apple and their smartypants ways, but usually there's a method to their madness.