For Audio: Add a "Group By" option for standard playlists (like there is for Smartlists)
In the context of using or ordering a list, that doesn't make a lot of sense. But I think I know why you want it: So you can easily look through a list and figure out which albums you have in that list, in a visual way that's easy to see. Standard playlist view can be sorted, but there aren't any good visual cues to show you where albums stop and start. Which is what group by Album does.
There's a good answer that's already built in though: Make a view that shows playlists. Then you can select a playlist in that view and use any group-by and/or sorting options you want. Bonus: You get to see Artists and Albums listed up top when using a Panes view, so it becomes even easier to review your playlists. A picture is worth 1000 words, so see the attached image for what this looks like in practice.
Brian.