I'd have to say either Shallan or Melody (I'm a sucker for redheads): Shallan because of her art and wittiness, Melody because she's awesome and you'd never have a boring moment with her around, and both because of their general attitude.
WHY ARE ALL THE GOOD GIRLS TAKEN?!
Though since Shallan is both betrothed and has... problems, I'd probably just go with Melody. She's awesome.