The unsung heros in my closet are absolutely my jumpsuits.
Pulling and outfit together is easy when the top and bottom match, and, oh wait, they're attached! Like dresses, they're the staples of one-and-done dressing. But unlike a dress, they feel a little tomboyish, and kind of edgy. They tell the world (literally): I WEAR THE PANTS. I collect them in neutral colors and patterns which gives me the widest range of styling options. (See a casual look HERE, a formal one HERE.) Whittling down dressing questions to a single 'WHAT SHOE?' makes the jumpsuit the speediest and most elegant blank canvas in my closet.
Always on the look out, I love scouring ASOS for affordable and interesting additions to my collection. They have literally thousands of options and innumerable ways to refine your search. Forever 21 has some good ones now and then, and if I want to splurge I shop Madewell or J Crew.