I'm amazed at the bad practices that students seem to have no problem with. The concept of DRY (Don't Repeat Yourself) is one that seems to elude many. I got some sample code yesterday from a student, fresh from graduation, with a 10-case switch statement with the same five-line block of code and one differing line in each.

The other one that amazes me, and that you mention in your list, is version control. There's no reason why every programmer in the world shouldn't be able to use Subversion.