Dagmar
Defender of the Bunnies of Skyrim
I like followers that can handle themselves and the Housecarls are among the best for both melee and ranged combat. Lydia is simply the natural choice since you can get her very early in the game and you have to become Thane of Whiterun to move the main storyline along. I also don't feel the need or desire to become Thane of any other capital city. I did it once to see what the other Thane quests are like but I've never done it since.I think someone likes lydia alot, not that the pic gave it away or anything. also i said unnecessary because the AI is retarded it should be smart enough to go around simple traps.
The AI being "retarded" doesn't make it unnecessary to direct followers, it makes it necessary.