i dont mean that kinda artist, lol, think musician!
It was a doke.. you know... ha ha! Or something.
Thinking musically, I have to concur with The Beatles' nominators.
Others that spring to mind (baring in mind that "influential" doesn't necessarily mean "good"):
Britney!!
Early boy bands (NKOTB? Take That... I dunno - not my field of expertise)
Run DMC
A lot of people I know would say Martin Carthy. Or maybe a group like Fairport Convention. Ooo! Wait... Blowzabella! (don't worry if you don't have a clue...)
Gotta have Elvis, if only for all the impersonators
I agree with Ms Posy r.e. The Smiths (although it does mean admitting to sharing taste with Terry Christian)
Radiohead
Whoever did the first dance tracks