There never seems to be enough shirts in your closet to accommodate the styles that your brain cooks up; a feeling of "I wish I had"s or "I need to get"s overwhelms. No closet exists that can accommodate all the shirts out there (although GQ's fashion closet tries mightily), so versatility is key in this battle of style preparedness.
The shirt you'll find that most completely adapts to your entire wardrobe comes in the form of a blue check. Similar to the versatility of a navy blazer, a blue check shirt can be thrown on and effortlessly exude style when all else fails. An all blue shirt would over power most outfits while all white will fade to background, but when the two combine in a gingham or window pane or tattersall pattern, it will grasp attention while accenting other pieces of your garb.
The most important decision is the type of collar to choose and should mirror the typical shirt you would wear day-to-day. If your go to is button downs, then go with that, and the same goes for semi-spread collars. However, a cutaway collar would take away from the versatility of the shirt, so even if that's your style, maybe opt for a normal or semi spread model. From there, find a pattern that works best for you, just make sure to keep it simple and limited to 3 colors at most (preferably just blue and white).
Check in tomorrow for a fashion piece that deserves your consideration and next Wednesday for another item that needs to be in your wardrobe!