Hm. Both are great choices, I honestly think you'd do well either way.
Sylvia is pretty, classy, and a bit old fashioned. Nicknames: Syl,
Sylvie, V, Via,
ViviDelaney is fun and newer but still not flaky. Nicknames: Del,
Della,
Lane,
Laney
Wow, I really don't know which one I would choose? Maybe
Delaney by a hair.
Three boys nappin', one mama namenerdin'
To peruse my top 100ish names:
http://www.behindthename.com/pnl/82589
He is becoming greater, I am becoming less
Bits of the journey here:
http://jodifriesen.blogspot.ca/And some family cuteness here:
https://www.flickr.com/photos/41705228@N08/