I love the name Ariella...my number one fave girls' name! I don't think it's over the top frilly or princessy, though the feminine sound of it is what really makes it appealing to me.
As for how I see an Ariella, I picture this adorable little girl I know who is so sweet with long brown hair and brown eyes.
Ariella Jane has a nice flow to it, though I'm not fond of Jane. My favorite combos are Ariella Maria, Ariella Jasmine, and Ariella Faith. Some other suggestions:
Ariella Elisabeth
Ariella Marie
Ariella Rene
Ariella Kathyrn
Ariella Josephine
Ariella Josette
Ariella Kate
Ariella Marin
Ariella Maren
Ariella Nathalie
Ariella Sydney
Ariella Brittan
Ariella Brooke
Ariella Christine
Ariella Felice
Ariella Grace
Ariella Hope
Ariella Haven
Ariella Iris
Ariella Jocelyn
Ariella Nicole
Ariella Payton
Ariella Presley
Ariella Rose
Ariella Roselyn
Ariella Violet
Ariella Zoe