If money is really no object, then obviously the 16-35. But, if money is an object then you ought to read Roger's take at Lensrentals.com on this lens:
I really liked my Tokina 11-16 f/2.8 when I shot crop - it's a great lens other than a bit of CA, but the 16-28 has one fatal flaw, at least for my work - it has strange and really bad rainbow flare (just Google for examples). If you never shoot into the sun or other light, I'm sure it's a fine lens, but I like to shoot backlit landscapes and architecture.
Interesting. Thanks for the tip. Followed your advice and those rainbow flares are a little strange. On the other hand, the internets don't seem to be exactly burning up with complaints. In fact, seems like more positives than negatives. Depends on one's needs and wants. Just mentioned it as an alternative for those to whom price is an object.
Did find this comparison as well. http://www.slrlounge.com/wide-angle-showdown-canon-16-35mm-l-ii-vs-tokina-16-28mm