TALKING HEADS - probably from the video jargon for a camera shot showing only the head & shoulders of a person. Newscasters are usually shown this way and it makes for boring TV. Another story says they were inspired by a military experiment involving talking mannequin heads.
LED ZEPPELIN - Jimmy Page was drinking with Moon and Entwhistle, who were *****ing about their band mates Daltrey and Townshend. They joked about the two of them starting a band with Jimmy, and one of them said "Yeah, that will go over like a lead balloon". When Jimmy formed his own band, he remembered this and thought "Lead Zeppelin" would be good, both from that conversation and the heavy/light contradiction similar to the band named IRON BUTTERFLY. They decided to drop the "a" so Americans wouldn't mispronounce it.
BLACK SABBATH - from a 1960's cheap horror movie starring Boris Karloff , suggesting a holy day of witchcraft.
THE VELVET UNDERGROUND - 60's experimental band associated with pop artist Andy Warhol, they took their name from a paperback book they found on the street - the book was about sex in America.
CHICAGO - Their first album was released as "Chicago Transit Authority", but the city of Chicago sued them because Chicago Transit Authority is the name of Chicago's public transportation department so they shortened it. Don't record companies check these things before they release them?