Title says it all. Shout out for any hero at all who hasn't had one yet, but you think desperately deserves one. For me, I'd have to say that the Flash is the hero I'd be most interested in seeing get his own animated series. And none of that computer animation crap that DC seems to be peddling nowadays. It works for Green Lantern, but I do not see it working for Batman or the Flash. I would much rather see a traditionally animated series for the Flash. I would love it if we all got to see some of the New 52 versions of his villains animated, but I would be down for their traditional looks as well. Captain Cold, Captain Boomerang, Mirror Master, Professor Zoom, Gorilla Grodd, Top, Trickster, Weather Wizard, Pied Piper, Abra Kadabra, and Golden Glider can all get proper animated debuts instead of simple guest spots on Justice League. Although, the JL/JLU version of Grodd was awesome and I'd love to see the same voice actor return for him.
Other heroes deserving of one would of course include Wonder Woman and maybe Aquman or even maybe the Doom Patrol or Jonah Hex, but I think the Flash has the most to work with.