My current addiction: Darkin Shyvana
After trying many different builds, I found one stupid build that only builds "I'm actually not dead" items after Triforce and I'm having so much fun with this one.
I go Tri -> Resist Boots -> DD -> GA -> Steraks ( -> Eternal Hunger if you get to it)
This is incredibly frustrating for opponents: DD makes burst seem like it doesn't work (even though it does), then at 3 items they see your GA icon and don't want to kill you anymore, and at 4 items even when they try your DD burn instead gets consumed by the Lifeline shield.
Coachless WPA seems to suggest this is a good build too so I'm not pulling it out of my ass.
Sidenote - one other relatively unknown interaction is that Red Smite triggers Cheap Shot, so you can take Ult Hunter without "wasting" a secondary rune instead of having to go the garbage Hexplate item. Really enjoying PTA + Ult Hunter.