I prefer
Lilia. It's a nice variant to the beautiful yet just a tad too popular
Lily, and I like the way it's spelled.
I'm not overexcited about the way the name
Liliana flows (it's always seems like a bit of a mouthful to me, though there's nothing wrong with it, really), and I can't help but see the name
Lila as a stripped version of the gorgeous
Laila or
Leila (but this is just me).
I think I would like the name
Delilah more if it wasn't for the amusingly over-dramatic
Tom Jones song "
Delilah" which starts haunting me every time I hear that name :)
Overall, I think all the names are nice, and there's nothing wrong with them in general. They're just not among my personal favourites.