I just stumbled on this thread - my name actually is Della Marie! Both of my names are family names. I disliked Della as a kid (it seemed to rhyme with a lot of things...) but I LOVE it as an adult. It's unique but uncomplicated and I receive compliments on it all the time. I find it interesting that it seems to be gaining in popularity (at least among the nameberry set), although I don't think it's cracked the Top 1000 yet.
Della Noelle is too repetitive, and Marie is b o r i n g in the middle spot. What about Della Faye?