I recommend visiting your local AT&T to try out cases. Several are currently 50% off. Here's what I discovered from the cases I currently have:
Supcase Unicorn Beetle (Amazon.com) - Grippy enough, little bulk added, clear enough back, perfectly placed cutouts, preserves the phones curve, has an integrated dimple, power/volume buttons are stiff....but you rarely need them since the Moto X "breathes", feels like it will protect the phone if dropped, small lip for laying the phone face-down, comes with a screen protector.
Case Mate Naked Tough Case (AT&T) - Clear case, little bulk added, excellent tactile feel of buttons....though they are silver, retains the phone's curve, no dimple, a bit slick in hand, feels like it adds adequate protection for a drop or two, haven't had it long enough to see how it holds up to scratches, small lip for laying the phone face-down
Speck Candyshell (AT&T) - Difficult to put on/get off, will likely protect your phone if dropped, a bit slick in the hand, no dimple, doesn't show customizations, a tad on the bulky side compared to other cases, adequate lip for laying it face down.
Ballistic LS Jewel (AT&T) - Thin TPU case with slightly enlarged corners for added protection.....kinda. Grippy, slim, smoked. Probably limited in the protection it provides in a drop.
Otterbox Commuter (AT&T) - Typical Otterbox Commuter case...will provide better protection against drops and such. Its very slick if you have clammy hands, and adds bulk/width to the phone. No customizations will show much.
Keeping the Supcase & Case Mate....all others are going back.....except the Otterbox.....maybe...I get a little rough from time to time