Just like the iPhone X, Apple's official cases are beautifully crafted. Apple sells three kinds of official cases for the iPhone X (silicone, leather, and a leather folio) in a variety of different colors. The leather case is our favorite, particularly in the "Saddle Brown" color (pictured) since it ages quite nicely over time. It provides reasonable protection from most drops to the sides or corners, the inside is lined with soft micro-fiber, and there are even metal buttons (most cases have cutouts that essentially recess the buttons and make them harder to press).
For more grip, the Silicone Case is the way to go. It's also $10 cheaper. Get the Folio Case if you want to shield the display from the elements and stash some cash and a few debit or credit cards.
Runner ups: