I often create playlists that contain one album or songs by one artist.  I select the songs I want and drag them to the Music source and drop them in the "New Playlist" that appears. It would be great if the name changed to something more meaningful after the playlist is created, e.g.

if the songs are all by the same artist:
<artist name>

if the songs are all from the same album:
[<artist name> - ]<album name>

Lukas