I'm sure there will be an EF 24-70mm f/2.8L IS USM lens at some point. There's a clamor for it, the EF-S 17-55mm f/2.8 IS USM lens is very popular for users of crop bodies, and perhaps most importantly, Nikon's 24-70 doesn't have VR (the Nikon equivalent of Canon's IS). The question is when... Note that there are rumors of additional lens announcements from Canon, expected Feb 8-9th. I'd certainly hold off on until then.