The build order that I use now is as follows:

Eye of Ekron 1
Fatality's 1
Hawkman's 1

I build Fatality first for the enhanced PD. I use the +22 PD Mod for Fatality's. Then I build Eye. Initially I only build both to 3.

After I have my Will and CD Reduc moving along nicely, I grab Starheart and max it out.

I get Blue Scarab as my fourth item and I max it out. I use the Blue Scarab Mod that gives 10+20% PD.

From here, I grab Pandora's for more PD and  that massive CD Reduc and Move Speed. I use the +5% Mod. I typically build to 3 to start.

My sixth item most of the time now (and it is subject to change) is Helm of Fate. You get more Move Speed at max level, you get 90 PD at max level (which is actually 120 once Starheart does its magic), you get plenty of Atttack Armor, and you have the ability to switch to Power Armor if needed (albeit reduced PA). A fantastic item all around.

From here just max level Eye, Fatlity's, and Pandora's. I usually max them in this order because you get the largest PD jump from Eye, then I grab Fatality's for the extra PD and Activatable, then I finish by making Flash even faster with Pandora's. You are, of course, free to make your own decisions based on how you play. Some people may very well likely prefer to max Fatality's or Pandora's even earlier for the activatables. I tend not to use them at all because 1) there are no swappable slots yet; and 2) you often dont need them anyway.