Ellis is one of the less used names in the currently popular El-family. It is the Welsh form of Elijah, by way of the Greek Elias, and has been consistently popular in Wales, where it is usually spelled ELIS.
Ellis Bell was the male pseudonym of Emily Bronte when she wrote Wuthering Heights. Ellis Marsalas is the paterfamilias of the noted jazz family, father of Wynton, Bradford 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.