Blizzard has released a preview of the Priest Tier 13 armor set that will be available in World of Warcraft Patch 4.3. You can click on the above image to view a larger version. Here's their description of the Vestments of Dying Light:
"Priests (and paladins for that matter) are often the most challenging classes to design ‘badass’ armor sets for, in contrast to the death knight and warlock, whose underlying concepts demand the unquestionably cool dark and sinister approach.
In this instance, however, the design asked for a bold, two-tone, ‘Venetian carnival style with creepy, soulless black eyes,’ which gave me a powerful, potentially edgy direction to explore. The set’s ‘Dying Light’ theme was visualized as a spiked, setting sun motif."
In addition to the Tier 13 reveal, Blizzard has posted a visual guide to priest Tiers 1-12 for Transmogrification purposes. You can view the priest's armor history after the jump, and check out Wowhead's guide to find all your old tier gear. Also, be sure to browse through all of the currently released Tier 13 previews.