Student and Teacher editions for the US;
ARE the same full program as retail versions
CAN be upgraded to later commercial version,
can be installed on 2 private use computers; i.e. not at school
CAN be used for commercial work.
cost LESS than any other form of upgrade.
As long as you're in a 4 year program, you're pretty much set.
And as a special note, i believe there is no standard PS version for the Student and Teacher edition, its only PS Extended. for 200$. I have CS3 Master Collection, and my upgrade to the standard edition is 200, extended is 350.