Other species seen in the east that some day may be found in North Carolina:

Blue-throated Hummingbird
(Lampornis clemenciae)

This mostly Mexican species is regularly seen in southeastern Arizona, and sometimes in southern New Mexico and Texas. A couple from Buxton reported an individual of this species coming to their feeder over the Christmas holidays of 1998. Unfortunately they were not able to get photographs, and the bird was seen for only two days.
www.hummingbirds.net/bluethroated.html