Don't like Effie as stand alone name, but I think it's a nice nickname. I knew an Effie whose first name was Jennifer, that works well.
To me, Effie as a first name sounds like you're making one up just to be different. If Effie was on my birth certificate, I'd be pretty pissed off once I was old enough to have an opinion on names!
It makes me think of two things: Heffer, as in cow, and "Eff off" as in fuck off! Whose to say when she'd older (in high school) she won't get one of these as a nn?
If my parents gave it to me as a nickname, and I hated, I could opt to not use it, but if it's on your birth certificate, where can you go from there?
Sorry, I don't like Corinne either.
(PS - Haven't ever been so out spoken on a name thread, before, I don't think!)