Heh! I had to spot out a dust mark (and I'vd had this D80 for less than 2 weeks)... I guess I'll have to throw caution to the air and buy a sensor cleaning kit... So a little light ain't so bad ;)
Sensor cleaning sounds like precarious business. You would never find me doing that... ^_^ I've just heard somewhere that too bright light i.e. camera pointed directly at the sun (maybe this isn't, but it looks like it) can burn the CCD sensors. Im not sure about the technical side of it though.