I know there used to be a few SE1.0 sites still around, and many got migrated to 2.0
Some moved out of SE altogether (such as parenting).
Are any still in 1.0 mode?
I asked this question in a comment a while back, but I forget exactly where.
As far as I know, PaleoHacks is the only existing SE 1.0 site. MathOverflow was recently migrated to SE 2.0, though: