:"Well, if the voltage that gets to the light bulb is always the same, for more light, the light bulb must have less resistance and the current in consequence will be higher."
This is an incorrect assumption - light bulb light output is dependent on the temperature of the filament - the hotter the filament, the higher the light output for a given power consumption.
That's why halogen bulbs give more light for the power consumption - their filaments run hotter than regular incandescent bulbs. A quick measure of this, in the Sylvania chart given by Paulster2, is the light temperature - a 3000K light temperature (typical of a lower power halogen) is 3000 degrees Kelvin (3000K), because that is the temperature of the filament while it is running. A classic incandescent bulb will be about 2300K at most; a higher output halogen perhaps 4100K.
As the filament temperature goes up, the percentage of the power input to the filament that is converted into light goes up (and the percent that becomes waste heat goes down).
However, a hotter burning filament also has a shorter life - you can see this in practical application if you look at the Sylvania chart, but also in the lightbulb aisle of your hardware store - there are 'long life' regular incandescent bulbs, that use the same, say, 100 W as other bulbs, but give less light (lower lumens), and have a lower light temperature (instead of 2300K, perhaps 1800K). They are much less efficient at producing light, but last much longer.
for more light, the light bulb must have less resistance
. It might just be more efficient at generating light.