Nixies: the Pixies' soggy, overlooked cousins. Recently I've been pondering why exactly they get so little attention. They are clearly overshadowed by Pixies. Their overall stat adjustments aren't quite as good, no Fly speed, and they lack Greater Invisibility at will.
However - and here's the thing that really makes me pause - Nixies are only LA+3. That means it's possible to buy off the level adjustment pre-epic. Is there any other creature that gets +8 to a casting stat, at that LA, without racial hitdice? Seems to me that (in a campaign that offered buyoff) this could be a powerful option for a Sorcerer or Bard; or even a social Rogue.