How would this differ from a playlist and/or Up Next?

I've been waiting for "Up Next" Since I migrated from Winamp - Being able to play a song, and then realize "I know what would go PERFECTLY after this", is very useful.

Or listening to music, selecting a much of tracks, and throwing them in the queue, without the hassle of creating a playlist ahead of time.

Very pleased!

I upgraded iTunes right after I wrote the post - Up Next is exactly what I was hoping for.