I think that the EF 16-35 needs a replacement because of the bad performence on f.2,8. And Nikon has one that is superior. So will it be a completely new one with the zoom range 14-24 with is.
I want one for shure
The EF 16-35mm was released 4 years ago, and the 17-40mm & 14mm were announced around the same time.
As Canon has problems with the super teles it has already announced (300mm f/2.8, 400mm f/2.8, 500mm f/4, 600mm f/4), is commited to it's "pre-announced" 200-400mm, and is probably planning to release new TS-E 45mm & 90mm, I wouldn't expect Canon to come with a response to the Nikkor 14-24mm any time soon.
Personally, I've bought the new Sigma 12-24mm, which does the work for me. It isn't as good as the Nikkor 14-24mm, but it is cheaper and available on the shelves.
I find the Nikkor 14-24mm very attractive, and the rumor about an FX Nikkor 10mm very interesting, which makes me think of either switching over to Nikon, or maybe use the money I'm saving to buy a Nikon D700 / D800 + Nikkor 14-24mm (+ 10mm, if announced), rather than spending it on more Canon equipment.