AD assassins pretty much build the same thing every game.
Most mages go ludens, zhonyas, morellos, void, and deathcap. Ocassionally you'll see a GLP, protobelt or liandries on specific champs.
Jax's first 4 items are always the same (tri,spear,titanic,steraks). Then he chooses either wits/randiuns/ga last, depending on the sitaution.
Darius and garen really only choose between building triforce or black cleaver.
I just feel like the game doesn't give you much room to be experimental with your builds.