Playlists in Aurora closely resemble your iTunes playlists, so you can easily identify which music you'd like to listen to. Aurora gets playlists from iTunes automatically, but may not keep up with changes immediately. Should a manual refresh be neccessary, select Alarm > Refresh Playlists from the menu.
Selecting music by album or artist is not possible, but you can simply create dedicated wakeup playlists in iTunes and use them in Aurora.
If you enabled EyeTV support, TV Channels will also appear as playlists in Aurora's playlists menu.
There is a special item in the playlists menu called No Playlist which you can use if you don't want to listen to any music when the alarm goes off, but rather use it to launch the attached item.