Ellis is one of the less used names in the currently popular El-family. It is a popular Welsh name in its own right, sometimes spelled Elis, and also an English surname derived Elijah, by way of the Greek Elias.
Ellis Bell was the male pseudonym of Emily Bronte when she wrote Wuthering Heights. Ellis Marsalis is the paterfamilias of the noted jazz family, father of Wynton, Branford and others, and some might associate the name with Ellis Island, through which millions of immigrants entered the United States.
There have been a number of Ellises on the big and small screen--in The Wire, Grey's Anatomy, and No Country for Old Men, among others. As a surname it's associated with designer Perry, writer Bret Easton and psychologist Havelock.
There is currently a female character named Ellis on Glee--whether that will affect the perception of the name remains to be seen.