I've done a ton of experimenting with aftermarket bulbs and come up with one conclusion - somebody's lying. I too am always looking for more light without pissing off oncoming drivers which is a tough proposition. Remember, no matter what bulb you stick in, you're still stuck with the same PATTERN because it's built into your headlight lens and reflector.

As far as "blue" bulbs go, remember that blue will actually cut down your light output. If you don't go up in power (generally wattage), you'll actually go backwards in the "light on the ground" measure. I've seen some "blue" bulbs that look more like night lights than headlights. They might look cool, but you can't see anything.

As far as wattage goes, I've heard of people frying stock harnesses with 70/80 watt bulbs and having no problems at all with 80/100's. Doesn't make sense does it? I'd guess that not everybody is measuring wattage the same way. I use an aftermarket HD harness just in case with my very carefully aimed 80/100's. Nobody'd flashing me and they put out a ton of light.

Generally speaking, I wouldn't recommend anything over 70/80 watt bulbs for two reasons. First, they'll bother oncoming drivers. Second, they might fry your harness. You make the decision that's right for you.