I dont know if this applies as well, but the plastic covers on my van were yellowed and really restricted the light. I wet sanded them with 1000 grit sand paper and buffed them with rubbing compound. That made them very clear again and they produce much more light.
The best headlight bulbs I've found are the Philips Vision Plus bulbs
They put out 50% more light with the same electrical wattage by using higher quality gases inside the bulb and more precise filament placement. There are suppliers in England cheaper than this one in California...look on eBay.
I do not use any bulbs with blue tint. These actually cause more glare to on-coming drivers and more glare in fog, snow, rain, wet road haze, etc.
I replaced the stock bulbs in my 2002 GC with SilverStars, and really like them. My headlights are 9007's, which are easy to find, but the fogs are something called a 9040, which is only about 40w, and are really hard to find. Sylvania doesn't make a SS in that size, but the 9005 is an exact fit in the fogs instead. They're about 70w, but so far I haven't had any electrical problems. Plus, they look great!
I get the XD5 off ebay. They are 5800 kelvin and you can get them in 55w or 100w. They are very bright and have a classy bluish HID look to them. I highly recommend them. However, whatever you change to, you have to do all the lights to the same or it will look funny with 2 or 3 different color lights going down the road.
KLS, thanks for the reply and info. The SilverStars are pretty much pure white. The state police here in Maryland are rigorous about not letting you drive around with the higher intensity blue tint or HID bulbs in your vehicle if it did not come standard from the factory with them. The next time I need to replace the bulbs I'll give your suggestion a try.
The one thing I have found is that if one bulb goes you may as well change them both...the other will usually only last about another month or so.