On my Warlock (main), I have no idea. I stuck at 500, but was having so much fun with all the new stuff that I never noticed when blues started dropping >500. On my Hunter, I made it a point of getting her over the 500 plateau quickly, so I started doing everything that promised 'powerful gear': strikes, Crucible (which I generally hate), daily Heroic story, and Flashpoint grinding. That stuff drops at higher light, so it was pretty quick to get through the 500 plateau.
It depends on what results you want to get. Once, i`ve stucked with Not Forgotten questline and i`ve decided to use pro players help.
Found this D2 recovery service. Now I use it constantly and should say it has become much more interesting to play. Highly recommended