Liongames.com has both PS3 and 360 versions of DMC4 on preorder at $55.99, and the Collector's Editions at $74.99. Dunno if those are deals or not compared to other sites, though.
EDIT: On further looking, the best price I've found is Familyvideo.com. $55.99 (both versions), 99 cent shipping. They also have DW6 at $57.68, 99 cent shipping.