The Beatles were undoubtedly the most imaginative band of all time when you look at at their innovations in the context of music of that day. Not only was McCartney the first bass player to take lead vocals and move away from the 'walking bass' to counter-melodies, but Ringo Starr was a left-handed drummer who rearranged the back-beat for practically every Beatles number. The Beatles was one of the first bands to write their own material too.
More than that, their imagination in the studio was unprecendented. The Sergeant Pepper album created analogue effects which other bands could only begin to match with the advent of the Fairlight CMI synthesizer. They used this to blend musical styles in ways that hadn't been imagined before and it can be argued that they gave birth to prog rock.
When you consider these facts together with how popular the Beatles were as live performers and how durable their music has proven to be, I have no hesitation in regarding them as having made more impact than any other entertainers.