So far if I had a choice of non-marriable NPC's for my character http://www.uesp.net/wiki/Skyrim:Lynly_Star-Sung would be the one I would choose for my character. But alas she was not marriable or atleast to my knowledge so -insert sadface here-
Borgakh the Steel Heart. Is who I settled on as well. Would have married Senna if it wasn't for the fact that you can't change her clothes and I prefer a woman who can lead a battle charge rather than lead a prayer. Lydia annoys me to no end. She 'fated' herself into a watery grave. As a housecarl all she is, is in the way. As a follower she's either in the way or on the otherside of the map. Yes that can be said for most followers but Lydia seems to have went back to the all-you-can-fail buffet cart for third and fourth helpings. Her passive-aggressive whining didn't help either.
Atleast when Borgakh spazzes out I can justify it as an orc being an orc. And honestly she had me at "An orc follows to the death." lol