Xenon Gas bulbs actually use less wattage for more light than halogens.

If your current headlights have replaceable bulbs, there is an inexpensive set of adapters that will allow you to plug H4 size bulbs right in. I've seen them for about $5. I'm watching for a set myself to update the bulbs in my '67 Fiat Abarth.

You can get Xenon Gas bulbs from a good eBay dealer for about $20 a set. Look for those bulbs that are in the 7,000K to 8,000k light color range. They will give more light in a white (almost blue) color that will give you the very best visibility for the least cost.

The 4,500K light range bulbs are somewhat yellow, and look like incandescent of halogen bulbs to other drivers.

Sylvania has been advertising the heck out of their version of the Xenon bulb, but they cost about 10X as much and in my experience don't perform as well as my eBay units.

If you have driving lights that have H3 size bulbs in them, you can upgrade to 100W or 130W Xenon bulbs quite cheaply.

Steve