The only thing I'd recommend doing to improve nighttime visibility with a halogen system is to get higher-efficiency bulbs such as Osram Silverstar (NOT Sylvania Silverstar), Sylvania Xtravision, Wagner BriteLite, and especially GE Nighthawk bulbs. These bulbs have clear glass and do not filter out any light, they simply have a more efficient filament that is more lumenous. The downside is that they probably won't last quite as long and they cost more (around $35-40 for a pair). For reference, a standard H3 halogen bulb puts out 1000 lumens on the low beam. a GE Nighthawk bulb puts out approximately 1150 lumens with the same power consumption. Not a huge increase, but still significant.

One other high-efficiency bulb that is difficult to find is something called "HIR" - halogen infrared reflecting. I've only seen these in 9005 and 9006 guises, and only a couple of times on eBay. You might be able to find them on Google. They work by reflecting the invisible infrared rays that all halogen bulbs produce back into the filament, making it burn brighter than a regular bulb. The seller claimed a huge improvement to lumenous properties with basically zero compromises. I have not personally tried these but I did find a review a while ago that favorably compared them to other non-HIR bulbs. The specs on them say that they produce almost 100% more light than a standard halogen! These are probably worth a shot, however they are pretty expensive for halogen bulbs ($60 for a pair).

It's easy to fall into the "Xenon" bulb trap because even reputable manufacturers make them. The Sylvania Silverstar is an example and is a ripoff (not only are they expensive, they put out less light than a standard halogen and also they only last for 150 hours instead of the standard 1000). Wagner TrueVision, LazerBlue, PIAA's stuff, and CoolBlue are all similar and should be avoided, unless having blue headlights and trying to look cool is worth driving blind at night.

So, in summary, here is some data to think about:

Standard 9006 halogen (low beam): 1000 lumens, 800 hour rated life $6
Sylvania 9006 Xtravision (low beam): 1060 lumens, 300 hour rated life $10
GE 9006 Nighthawk (low beam): 1150 lumens, 250 hour rated life $14
Toshiba HIR 9006 (low beam): 1800 lumens, 800 hour rated life $27
Sylvania 9006 Silverstar (low beam): 910 lumens, 150 hour rated life $20
http://reviews.ebay.com/quot-Xenon-q...:-1:LISTINGS:6