I'll take a shot at it.
First off, chalice/Athene's has definitely become kinda... meh, as of late. The Mana Font passive, which used to increase mana regen as your mana got lower, now restores a percentage of your maximum mana as your mana gets lower. In effect, unless you have enough mana to go with it (I sometimes do Archangel's + Athene's), you won't generate nearly as much mana as you used it.
Situational builds aren't something that can be ignored, because it can affect build order and build path. But, Zhonya's and Rabadon's have stayed pretty essential on her regardless. Morello isn't too shabby, and as I mentioned earlier, I sometimes go Archangel's and Athene's because it does give some pretty great sustainability mana-wise. Void Staff is obviously a good choice if they have magic resist, but sometimes enemy teams are derpy and don't build it at all, in which case this isn't as necessary. Sorcerer's Shoes and Ionian Boots can be interchangeable; I personally don't go Ionian unless I have the right mana path to sustain the max CDR I tend to get with those boots. If you have an open item slot, you can always throw in a GA or something, Liandry's is an option with your W slow and all, but it's your choice.