The darling of designers has been halogen lighting for its sparkling intense light.
A new study shows that energy-efficient small metal halide bulbs can replace halogen, compact fluorescent and incandescent.
"Low-wattage metal halide lighting systems offer high-intensity light output in a small, energy-efficient, package. Recent developments in the technology have broadened their range of applications, replacing higher wattage incandescent lamps, PAR halogen lamps, and compact fluorescent lamps in recessed downlighting, accent lighting, and retail lighting. Low-wattage metal halide lighting systems provide good color rendering properties and good optical control."
This set of images is from Venture Lighting. The center image is a proprietary product they are making for commercial use (the wattage is way to much for residential).