Notes about lamp types:
Incandescent (conventional filament bulbs)
First of all we can say that pretty much whatever you need to use a light for, efficiency-wise conventional incandescent lighting is the worst choice (typically 10-15 lm/W) (lm/W = lumens per watt, dependent on bulb wattage). Most of the energy used is turned into heat. Furthermore, they rely on a filament which by its nature is fragile and has a relatively short life span (typically 750-1,200 hours).
Halogen (Quartz Halogen or Tungsten Halogen)
Halogen lighting is more efficient than incandescent lighting - typically 20-25 lm/W. Bulbs, including halogen tubes and capsule lamps are also more compact, have a significantly longer life (typically 2,000 - 2,500 hours) and give a whiter light. Halogen lamps are best suited to high powered exterior flood and search lights, and to interior spot lights. Their main disadvantage is that they run at a higher temperature and because the gas inside is under higher pressure, they are occasionally prone to bursting. So it is safer if halogen bulbs are used within an enclosed lamp. Also, when replacing any halogen bulb, do not touch the glass envelope. The salts in your skin oils penetrate and weaken the glass. The bulb not only has a shorter life, but when the bulb dies the filament doesn't merely burn out, but rather the bulb envelope shatters.
Xenon bulbs are more efficient than halogen (typically 24-30 lm/W). Similar to halogen lamps but up to 3 times brighter and have up to 3 times the life span (typically 8,000 - 10,000 hours). Xenon lamps are best suited to high powered exterior flood and search lights, and to interior spot lights. Because xenon gas is filled at a lower pressure they are not prone to bursting and are therefore safer. As with regular halogen bulbs, xenon bulbs should not be handled directly.
CFL (Compact Fluorescent Light)
CFLs use around 20% of the energy required by an incandescent lamp of similar output - typically 46-72 lm/W. Because of their compact shape, brightness and diffuse illumination they are well suited to wide area illumination in both work and living areas. CFLs last about 8-15 times longer than incandescent lamps (6,000 - 15,000 hours). The colour temperature is warmer and 'friendlier' than fluorescent tubes.
These really are a very good, energy efficient method of bright area lighting - typically 70-100 lm/W (Lifespan 6,000 - 15,000 hours). They are the most efficient room/space light available. Many people find the colour temperature too cool for living areas but they are ideal for galleys and other work areas. Their very low power consumption and diffuse illumination make them a good choice for deck lighting on fishing boats and workboats, although they can be slightly temperamental to start up when operating at very low temperatures.