Alot depends on whether you want to be pulled over or not. Most of the aftermarket bulbs aren't legal for street use. If you want to stay safe, go with the Cool Blues or the Silver stars. Basically the stars cost more for the whiter light. The more you spend, the better you get.
I have silver stars in the lows, cool blues in the highs. My high beams will be replaced with silver stars. Vastly superior, but the cool blues are also superior to the stock lamps.
If your budget allows, go with the Silver Stars.