The numbers you seek are all relative....
Let us say that a marque has 500 small light bulbs and that each light bulb is a 25 watt light bulb. This means that each bulb uses 25 watts per hour. Lighting up the marque for one hour then uses (500*25w) or 12,500 watts. If the marque is lit for 10 hours per night, then the amount of energy used just on the marque climbs to 125,000 watts for just one night; and 54,125,000 watts in a single year of 365 nights. This does not include the building, accent, doorway, or spot lights used on and about the building.
The amount of energy used for any one light show, on any one building, etc,,, depends upon the sum of the wattage of the light sources times the amount of time they are used.
Getting back to the marque example, some businesses are moving towards LED lights which use far less energy for the amount of light, or lumens, they give off. Other businesses are moving towards an assortment of timers and photo-electric cells to guide the turning on and off of their lights.
Home owners and apartment dwellers can do the same. They can also use a number of different types of CFL light bulbs which use far less energy than incandescent light bulbs to produce the same number of lumens, or amount of brightness. Towards "decorative" lights, many people are shifting to strings of LED Christmas lights, LED rope lights, and LED decorations; both for use at Christmas and on the patio in summer. Those that make these changes in a short period of time, often report that they can notice the difference on their power bill; this is an indicator that the actual power usage savings is great enough that they can readily notice it.
When considering the amount of energy used to light up a marque and then the potential energy use savings by switching that marque to an LED system, the numbers are bigger and more satisfying than the numbers in a single family residence due to the sheer number of light bulbs involved. But, as a number of different, individual residences all switch to energy saving CFLs, LEDs, solar lights, and take up additional power savings activities the savings can be tremendous. For example, within the past two years the State of California determined that 10% of all of their electricity usage is being utilized by TVs; both business and personal. Sure, a number of those TVs are probably located in bars, taverns, lobbies, and clubs. But, my guess is that a far larger percentage of them are in private residences.
There is a lot of collective energy savings potential within private residences. On the other hand, baseball fields that are brighter at night than during the day, large marques, and places like the Vegas Strip do make one ask about energy consumption.