Thats always a difficult question. Its like picking your favourite food, or the girl you liked more in your life (wait, thats easy is'nt it? ).
Well, i 'd say the first one:
Neon Genesis Evangelion, or Shinseiki Ebangerion in japanese and New Birth Gospel as in greek meaning.
Its a lot more that i like and love but if i had to choose one, it has to be NGE....again and again and again.........