So, not having an iPod, but having a huge library, I like to have mix cd's in the car. When I can, I like to make them so they flow just fine. However, lately I've been letting iTunes do it so I get a fresh approach. This is the smart playlist solution I've come up with for doing 'genre mixes' with my favorite songs:
Playlist #1:
Genre -> is -> Rock
My Rating -> Is greater than -> ***
Limit to -> 77 -> Minutes -> Selected by -> Random
Name this playlist: "CD Rock Mix 1"
That's all well & good, but when I want to make another Random Rock CD & I do not want any of the songs from the first mix, I do this:
Playlist #2:
Playlist -> is not -> CD Rock Mix 1
Genre -> is -> Rock
My Rating -> Is greater than -> ***
Limit to -> 77 -> Minutes -> Selected by -> Random
Name this: "CD Rock Mix 2"
This way, I can continue to make mixes in the Rock genre that will not have the same songs in them. Each time I make a new playlist, I just be sure to select "Playlist is not..." and include all the other playlists.