Hoover
Yes, Geoff, "hoover" is often used for "vacuum cleaner", but we only use it as a noun. In the UK, it's also a verb, as in, to hoover the carpet. I can't think of any instance offhand in U.S. usage where a brand name has become a verb, with the possible exception of "Brillo"; my wife used to say that she would need to brillo a frying pan.
(In case outlanders don't have this, "Brillo" is the brand name of a metal-fiber scouring pad.)