I really liked Abigail and it was on our list for DD, I also liked the meaning "source of a father's joy" or something along those lines.
We would always shorten it to Abbie, you can do Abbey or Abby too but I like the "ie" ending. I actually went to school with 4 Abigails and they all went by different spellings. I also feel like the name has lost some of it's popularity in recent years (but it's still classic, not like say Ashley or Jennifer) so if we used it for this LO (if it's a girl) I wouldn't worry about her sharing her name with 3 other girl's in her grade. That tends to vary by your area though.