'Standard' light bulb shape and golf ball shape. The 'standard' shape is also known as GLS (general lighting service).
The low energy round lamps are generally not as bright as the spiral shaped alternatives, as they have a glass cover that will slightly restrict the light output.
Some people prefer the covered round lamps to the low energy spiral bulbs, because they are more aesthetically pleasing when the light bulb is visible. If the light bulb is not going to be visible, then you should consider a low energy spiral bulb instead as it will probably be brighter.
