Marie Romanova
Marie ("Mashka") was one of the three elder sisters of the famous Anastasia (the other two being Tatiana and Olga). Of the four sisters, I find Mashka the most appealing, personality-wise.

Queen Elizabeth I
She'd have some great stories! Plus, I could get some authentic Renaissance recipes from her... or rather, from her cook.

Emperor Augustus
Somehow I've always liked Augustus; his decisions mostly seem logical to me, and we could have good conversations about urban planning!