I ended up going with the skirt suit because something about pants suits screams "CASUAL" and "HILLARY" (as in Clinton) to me. And I pulled a hybrid for my shirt. It was both a button-up and a silk blouse. I wore a silk button-up blouse with a fancy ruffle collar (I wanted to wear something fun and festive and fancy to signal it wasn't just any other work day!).
Here are close-ups of the ruffle details from eBay (so you can see it's not just any old button-up):
|Whole blouse (mine is gold)|
|Collar and cuff detail|
Originally tried black tights but something seemed a bit off.
And as the kind commenter AnonInfinity pointed out, collar out seemed a little wonky, so: