Several readers recommended Dave Dugdale's video lens comparison review of the Canon 16-35mm II vs the Tokina 16-28mm. Keep in mind that even though Dave is making this comparison to try to decide which wide angle lens to use on his full frame Canon DSLR the Tokina 16-28mm lens is also available for use with full frame Nikon DSLRs.
I have to say that it's pretty amazing that the Tokina looks so good compared to Canon's best L series lens wide angle lens when it's only half the price of the Canon 16-35mm.
I can attest to the fact that the Canon 16-35 is built like a tank! I have the old model that I got in 2003, and it is still as good as new.
Oh by the way, while you are over at Dave Dugdale's site, he has a bunch of tutorials and resources for learning to shot video with your DSLR.