Which do you prefer and why? I know they are pronounced the same but I don’t know which spelling to consider!
Thank you 
Definitely [name_f]Annabel[/name_f]
I prefer [name_f]Annabel[/name_f] but the litte girls I know with this name are all -elle.
I prefer [name_f]Annabelle[/name_f]! It looks sweeter to me, though both spellings are lovely.
I prefer [name_f]Annabelle[/name_f] because I think it looks more “balanced” than [name_f]Annabel[/name_f] because of the double n and double l if that makes any sense.
Can’t really decide, I think both spellings are charming in their own way and convey something different in their own way. [name_f]Annabelle[/name_f] is definitely more frilly and is dainty, but [name_f]Annabel[/name_f] is fierce but at the same time sweet.
I like both, but prefer [name_f]Annabelle[/name_f] because the spelling looks more sophisticated to me!
I also prefer [name_f]Annabelle[/name_f]. [name_f]Annabel[/name_f] looks incomplete to me.
I much, much prefer the [name_f]Annabel[/name_f] spelling.
I prefer the streamlined, classic spelling of [name_f]Annabel[/name_f]. It is plenty feminine with a single l.
I like [name_f]Annabelle[/name_f] more. As others said, it looks more complete.
I prefer the streamlined [name_f]Annabel[/name_f] spelling. [name_f]Annabelle[/name_f] looks frilly to me, but then so does [name_f]Isabelle[/name_f]. (I prefer [name_f]Isobel[/name_f]). It’s really just personal taste! 
I prefer [name_f]Annabel[/name_f]. [name_f]Annabelle[/name_f] just looks overly frilly, though I do really like [name_f]Annabella[/name_f], which is even more so.
I love both and it would mostly depend on the middle name to be honest but if I had to choose, probably [name_f]Annabel[/name_f] :).
I go back and forth but usually prefer [name_f]Annabelle[/name_f]. Agree with PPs that it looks more balanced.
I much, much prefer [name_f]Annabel[/name_f]. So much so that I love one name, and can’t warm to the other. [name_f]Annabel[/name_f], being more streamlined and less fussy, feels smarter and more stylish. Whereas [name_f]Annabelle[/name_f] feels over-the-top and over-feminised to me, almost like you are insecure about the name so you have to over-emphasise it. (I can’t believe I have such strong feelings about spellings!)
I have the same thoughts about [name_f]Isabel[/name_f] and [name_f]Isabelle[/name_f].