I don't understand how iTunes works.. I thought when I added files to iTunes it would be stored as a library, but instead I guess iTunes sees it as a playlist.
What I simply want is that iTunes would see my E:/ drive as music library, that it automatically adds the music that i put there, that I can simply plug in my iPod Classic and push Synchronize and it's done.
Is this possible in iTunes or is there other software you'd recommend that can take care of this?
If you are choosing to live within the Apple ecosystem, you are going to be stuck with all of Apple's restrictions, which is unfortunate in terms of ease-of-use.
You can sync playlists to an iPod, and if you're not paying attention, you can lose everything on the iPod in the process, or if you open the settings for your particular iPod when plugged in, you should find the option to "Sync only checked songs and videos" and "Manually manage music and videos," which hopefully should make the software act a little more intuitively.
You still need to have your music in the iTunes program to manage it through iTunes.