Nikon has a 14-24mm f/2.8 no VR lens, and then they have a 16-35mm f/4 VR lens. I really fancy that lens, on a Canon however it should be 15mm at the wide end. Both lenses are better than there Canon counterparts and cost roughly the same.
People expected the Tokina 16-35mm f/2.8 as a Canon 14-24mm, however the photozone.de MTF chart for that lens does not show comparable performance to the Nikon 14-24mm.
The 17-40 never really struck me as a FF lens. People always harp up and down for a EF-S L lens, in many ways I feel like the 17-40mmL is what they are looking for.
For me it is going to be the Samyang 14mm, unless Canon releases a 17-40mm replacement with IS before April.