You will be able to return nooks to stores once the stores actually have them. I returned the cover I preordered to a local store and exchanged it for another.
That said, the biggest failure on B&N's part with the nook is their severe under-estimate of the demand. The second biggest failure is their customer service not really understanding what to do (in any aspect, from simple questions to returns like KMWing had to go through) with an electronics device. The customer service issue will hopefully be re-evaluated and fixed once the preorders are all fulfilled...which is now estimated to be in February.
As for everything else, seems to be going fine, in my opinion. They even released the first software update that has improved things quite a bit (still not fully there yet, but I'm sure more updates are coming).
Enjoy your nook, KMWing! I certainly like mine.
K.