Do you want better visibility, especially in rainy or foggy days, or do you prefer better matching colour?
For visibility you'll have to choose an hotter colour bulb like the Osram Night Breaker Unlimited (around 4350 K) or the Philips X-treme Vision +130%.
For better colour matching you can either choose the Osram Cool Blue Intense or the Philips Blue Vision Ultra.
For offroad use you can use the Osram Cool Blue Hyper.