Playing mostly as a sneak archer and not being very strong in close combat I have to have a tank to aggro the enemy when I0m outnumbered. Also I need a mule to carry all the loot, and I like to have some company.
I've been using only Lydia for now (I'm lvl 27), and despite a lot of negative comments, I quite like her, I can still sneak on most opponents enough to take them down with my bow even when she follows me.
She doesn't get too much in my way and my character is quite attached to her after all the mess they've been through together

If I have a bad feeling I just tell her to wait behind, go exploring and decide what to do. I usually can take down a few guys by mayself, the just run back towards Lydia making a few ambush and let her kill the ones that are still alive.