If people are likely to take all the classes, then the progression could be:

C# of VB/ C / C++ / Java or perl or etc.

This would allow those who stop after the first year to still know something.
An alternative would be:

ASM/C/C++/VB or C#

This would be a progression from low to higher level languages, and would give the student a much better understanding of the workings of the computer. However, this is high school, so I expect the progression will be something like this:

VB/TCP/LSD/whatever.