Best first line of a song.

Eli's Coming I haven't read the other answers. Hope this hasn't been used before.

Just got paid today got me a pocket full of change. ZZ Top

There is no better first line to a song than this:

"Let's drink to the hard working people"

from "Salt of the Earth" by the Rolling Stones. Keith Richards sings this line.

Hello darlin'.

Counting Flowers On The Wall, That Don't Bother Me At All