From what I recall last year's promo was that you could either get the $199 iPod nano or the $299 iPod touch. I'm pretty sure the shuffle and the classic weren't eligible. You could buy any of the iPod touch models available at the time and use the $299 towards the more expensive models.
In previous years, I believe you were given I think a $150 (or maybe it was $199) rebate on the nano, but you could put that rebate towards the other iPod models that were available back then.
Until the promo is announced, you can't be sure which iPod models will be eligible.
And I don't believe refurb models are eligible. I think you have the get a new computer from the education store.