iTunes has always had a shuffle option that will randomly play songs from your song library, playlist, or CD. With version 4.5, there is an improvement on this concept with “Party Shuffle.” This special list creates a dynamic playlist. It will show the last X songs played and the next Y songs coming up. It optionally gives weight to highly rated songs. This is not that different from shuffle (which is still there) except I’ve found it very useful to go back and see what just played or what is coming up.
In this snapshot, the entire album Dark Side of the Moon (46 minutes) entered the shuffle because I imported that as a continuous song (no tracks.)