Maybe I'm an edge case, but I have never once had to deal with a whiteboarding session in a single interview I have been in. Though, this is obviously a small sample. I've worked at one startup, largely contracted otherwise, and am just now looking to join another.

Largely my experience has been 1/2 to full day pair programming sessions, building a sample application that does something reasonably nontrivial, or a combination of these two.

I really personally enjoy this practice. Even though a day of billed hours is a large opportunity cost, so is the expense of potentially hiring a bad fit for the team. It goes both ways.