I like to keep all my music on my iPod and listen to it on random but like to hear certain songs more often. I also rate my songs based on play count and when they were last played
To this end I have created a complex set of playlists to help me rate and manage my collection.

However seeing as most of the playlists aren't for listening to I told iTunes only to synch certain playlists and leave others off the iPod.
Doing this however only uploaded a few hundred of my songs onto the ipod and I want them ALL on the ipod.

The question I ask you is how do you keep certain playlists on the iPod while having your ENTIRE library on it as well?

If I am missing something simple please feel free to shoot me.