Njada Stonearm.
She might not become an oddly sweet and soft-spoken person when you marry her, like Taarie and Aela (seriously--both of those chicks turn into softies when you marry them, but she is far from boring and has additional dialogue, aside from the usual "bad wifey" stuff (i.e. saying your houses all svck, that living in Riften will make your kids little pickpockets, etc) and even does that cute humming thing!
Also, she is a more than a capable follower who is equipped with weapons and armor that match up nicely with her top skills (albeit that her Hide Armor totally svcks--I just give her a special set of Scaled Armor, sans the helmet...she isn't Njada with a Scaled Helmet, trust me).
And, this might just be a plus for me, but she isn't essential, which makes gameplay a lot more dramatic with her as a follower, or just having her around, say, at Lakeview Manor when you get attacked by giants or a dragon (she especially scares the living crap out of me whenever she fights a dragon!).
And despite her oddly colored hair (same with Senna--WTF? Is dying your hair grey all the rage in Skyrim or are they seriously that old?), Njada is, oddly enough, pretty cute too (at least for an NPC in a video game), in a very odd way.
And hey, it beats having her mouth off to you all of the time when your the Harbinger of the Companions....