As how the story continues, Keima-sama has started to realize that real girls are not that bad (as how he thinks about them prior to the start of the story). BUT, for me -- Keima-sama will DEFINITELY be contended his ideal girls -- his angels from the 2D world, nothing more, nothing less.. :))
But if I must choose among the girls (for the sake of just choosing :))), here's my bet..
CONQUERED GIRLS: Kanon Nakagawa :))
DEMONS: Haqua du Lot Herminium :))
2D GIRLS: Sora Asuka :))