The long rumored Canon EF 14-24mm f/2.8L is coming, perhaps by the end of 2013. Nikon already has its AF-S Nikkor 14-24mm f/2.8 lens on the market and Canon is just playing catch up. In addition, the EF 17-40mm f/4L and the EF 16-35mm f/2.8L II are also up for replacement. The new lens may be slightly narrower on the long end but aperture may stay at f/4 and comes with IS.
The schedule of the new lens release may slip into early 2014 but Canon is eager to round out the lineup of its wide angle, full frame lenses now that they have successfully released the Series II and EF 200-400mm Super Telephoto lenses.