The younger generations are leaning toward two thousand ten because they think the other option "sounds weird". You know, they don't recall that we didn't say one thousand nine hundred ninety-nine, but instead said it was nineteen ninety-nine. We switched to the two thousand back at the turn of the century, but do we want to stick with it? Once we start adding more years to it, doesn't it kind of become a mouthful?
Which will you be saying tomorrow? I am rooting for Twenty Ten. To be perfectly honest, I expect to be writing 2009 well into March on anything that needs a date anyway!