I'm most waiting for JoJo's Bizarre Adventure Part 7: Steel Ball Run to get adapted. It's pretty likely that it'll happen, though I'm a little worried David Pro might stop after Part 6. But Steel Ball Run is far and away the best JoJo, and will probably immediately slot into my all-time favorite anime series if/when it gets a proper adaption.
I'd love for 20th Century Boys by Naoki Urasawa to get an anime adaption too, though I guess I could always try and track down the live-action film adaptions in it's stead.