I have finally started watching Star Trek Voyager after rewatching almost every episode from The Next Generation (yes, I had been putting this off for a looong time). The character I am most impressed with is of course the holographic doctor, since he is surprisingly the roundest character around.
One of the doctor's abilities as a self-conscious hologram was to make himself solid or ethereal at will. Long introduction? Don't worry, we'll get right back to our dream.