Personally speaking, I would go for the refurb model.
The benefit of getting the new machine is:
a) Slightly faster processor, which you're not really going to notice (there are benchmarks floating around - if you want to check this for yourself).
b) 802.11n wireless - but you can get a wireless update for a couple of bucks from Apple to enable the refurb model to use that standard and bring it up to speed (no pun intended!).
c) Slightly bigger hard drive (an extra 40GB) - as it's a doddle installing hard drives in MBs, you could do this yourself and if you get an enclosure, then you've got a pocket drive too!
d) Improved Superdive - I think it's now 8x compared to 6x for DVD; slightly faster admittedly, but if speedy DVD burning is that important, you would probably be considering an external FW burner anyway.
As I say, I would go for the refurb model as the above doesn't sound like $300 worth to me - I would either spend some or all of of the savings on more RAM, hard drive and other accessories.
Also, don't forget it's cheaper buying the 2.16GHz white MB with a bigger HD to match the 2.16GHz blackbook, than it is to buy the latter. Effectively, you are paying extra for the color - but they doo look so good!
For what you're spending, the refurb is the better value - in my opinion anyway!