As of the release day for Magic: The Gathering--Dragon's Maze (see "'Dragon's Maze'"), "Voice of Resurgence" is the hottest card in the set, as measured by dollars sold through the TCGPlayer.com Website.  TCGPlayer.com is the largest collectible card marketplace on the Web, with hundreds of brick and mortar sellers listed.  The dollars sold are measured from April 22nd, when Wizards of the Coast released the full set list, through May 1st and reflect all transactions on the site.  Average price over the same period is displayed.
 
The price of "Voice of Resurgence" is currently well over the pre-release average, so the popularity of the card is still accelerating.  We'll be doing another report, updating the information in this chart to reflect post-release activity, in the coming weeks.
 
"Ral Zarek," the #2 card based on the chart, was selling for the top price during the pre-release period, although its dollar volume was second.

Sales data courtesy of TCGplayer.com, the Internet's largest collectible card marketplace with hundreds of brick & mortar sellers listed.