Ball and Stick
Balls with sticks really look nice but they are not obvious in PyMOL:
hide lines show sticks show spheres set stick_radius=0.1 set sphere_scale=0.25
show sticks set valence, on set stick_ball, on set stick_ball_ratio, 3 set stick_radius, 0.12
You can adjust the two numbers above to your taste.
Ed. As of 0.98bXX there is a GUI-enable Ball & Stick representation available to users.