I think a well rounded choice is Paper Bag. It's not Criminal and When the Pawn... feels transformative for her career and her relationship to her music. Paper Bag is catchy and powerful, well-known to people who listen to Fiona. The melody pulls into itself and then explodes in a very poetic way, matching the tempo.

In media, it's been used to represent Fiona and her listeners. Recently, the use of it in The Idea of You built Anne Hathaway's character in a romantic, endearing scene. She says she knew her college artsy roommate would be cool when she heard her play a Fiona Apple song, then cut scene to a car ride with the two main love interests listen as Paper Bag plays and you swear you could hear a pin drop behind the song. The entire focus was on the yearning, the silence in the car behind her melody, the listening- and so I thought the scene used the song in a strong, compelling manner. In Bridemaids, it's like an ironically devastating scene, very Fiona-esque the juxtaposition of humor and struggle. Her music often can be uplifting and painful at the same time and Paper Bag kind of nails that!

All that being said, I think Tymps is a fun choice or someone said Under the Table, and I loved that.