Aircraft: .55 lb to 55 lb must be registered with the FAA
Pilot: Fly for fun or education anything up to 55 lb with no certification.
I did my Commercial Drone Certificate last month, since I had to go to the FSDO anyway to renew my CFI. Fairly painless, you never know when someone will call with a job to film real estate (or sunbathers at the nude beach

)!