You DO NOT have to be enrolled in order to get the discount. If you have an acceptance letter or email address from the school, they will give you the discount. In my buying experience, usually using the education discount but on a few occasions buying refub computers and ipods, the best education discount deals happen in June when Apple runs the buy a mac get a free ipod deal... during which I usually sell my free ipod and end up with a cheaper machine.
However, my refurb experience has also been excellent. I bought a refurb macbook to replace an ibook I sold before moving to my current MBP. I got an fantastic deal on it and it served me well for the 6 months I needed it.
You might want to check out Amazon also.. no tax immediately makes it a pretty good deal usually, especially since they have decent rebates on occasion.