M&V and E&V. Vanessa's in my top five all-time favorite character list due to her confidence, strength, quick-thinking, courage and pursuit of the truth, so I love her dearly. Which is why the whole "pulling the gun on her" thing clinched the show for me; half jumped out of my seat with a "Holy crap she's gonna die" moment.
From there, over the course of about 10 episodes, Madlax's relationship with her slides from "naieve pest who's paying me money and attracts bullets" to dear, dear friend, as both teaches the other to survive in their respective worlds (physical struggle for Madlax, emotional for Vanessa).
As for E&V, they've got this snarky relationship that's adorable. How much you want to bet they're both sharing a coffee whenever they're not on camera, rolling their eyes over the latest bit of silliness Margaret has gotten herself into (see: the Miss Margaret, Please Don't thread).