RE: Express 1MX shirts. I buy a fair bit of clothes at Express but I've never been fond of these shirts. They seem to wrinkle excessively and some feel a bit cheap (they're made of varying materials, though. I have one that's fine. YMMV.) I prefer wrinkle resistant stuff, so one thing I do is lightly pinch the material while at the store to see how prone an item is to wrinkling.
You can probably find equivalent (or better) dress shirts more cheaply if you can find brands like Kenneth Cole discounted at big stores like Macy's. This happens fairly regularly. Note that "modern fit" shirts will fit more tightly around the waist/stomach. You should try it on, even if it means unpacking the damn thing and pulling out all of the pins.
A simple and versatile item is a black (modern fit) dress shirt. Sharp and serious with slacks, or you can wear it untucked with jeans for a casual look.