Don't forget that an OEM version is (Technically) locked to one PC, and cannot be transferred to a new one. (Or even a new/replacement motherboard in theory - although most seem to get away with it.)
There is no such restriction on the retail version. For the cost difference I would probably go retail.
As said above, you *Can* do a clean install of an upgrade version - but technically you will be running unlicensed software.
Again, I believe student/teacher editions are only licensed for use by the student/teacher.
However, in all the above cases the software runs without problems.