A classic among classics is Pacman, which has variants continually being launched. One such remake is Pakman, whose main difference to the original game is that it has realistic 3D graphics.
As the whole Pakman game is in 3D, it gives you a different sensation to normal, and even seems more complicated. As for the rest, the objective is the same: run through all the labyrinths eating everything you find at the same time as avoiding the ghosts. The large number of different bonuses you can win is outstanding, as too is the ambient music and the fact that it supports playing with the joystick.
Pakman is totally free.