I would suggest the Philips X-tremeVision.
Other things to look at is polishing the headlight lenses, or replacing the assemblies if the reflectors inside have faded from age and heat. Make sure your charging system is working properly, and ensure the wiring at the bulbs is tight and free of corrosion.
Even new stock bulbs will be an improvement if the current ones are a few years old. I've tested beam hotspot brightness on a few different bulbs. A well used bulb was 25% dimmer than a new stock unit. An X-tremeVision bulb was 7% brighter than new, and a RacingVision bulb was 17% brighter.