Even before Day 1 Digital officially starts, there are some full retail games available digitally, including FIFA 13 and Dead or Alive 5, and older games Starhawk and Mirror's Edge.
Along with that stuff is way too much quality PSN-exclusive material, including Tokyo Jungle and Hell Yeah, both of which were reviewed favorably by Joystiq (in case you missed them!), along with Marvel vs. Capcom Origins, One Piece Pirate Warriors, and more.