I would love to see Fantasia sing "Proud Mary." Didn't she do it in the auditions? I think she has the energy for it and it would really get the crowd going! "Say A Little Prayer" could be a fun toned down number that she would surely spice up a bit. I also think she could emote Billy Joel's "Just The Way You Are" really well. Diana Krall proved the song can also be wonderful when given a feminine touch. Chaka Khan's "I'm Every Woman" could also be fun.
I think Diana could do well on a Selena song if she wants one of her performances to be toned down. I always thought Jasmine could cover Selena well, but I think Diana could too. "Dreaming of You," and "I Could Fall in Love" would be good choices. She might also have the the power to tackle an Anastacia song too, like "One Day in Your Life." I always think of power and huge vocals with Diana, so maybe she could handle Bonnie Tyler's "Total Eclipse of the Heart" or Celine's "It's All Coming Back To Me Now." Back in the Top 32, Simon told Diana she reminded him of Christina Aguilera when she was nice, and in fact I think Diana could really rock the house with one of her songs. If she pulled off "Fighter" it would be awesome!
So those are just some thoughts... we'll see Tuesday I guess!