I have been using the Silvania Silverstar Ultras and they are significantly better than stock. Stay away from colored lights, you can look up all the info and color charts online but humans see best with white light. Also, do not concern yourself soo much with the kelvin rating of lights, you are interested in lumens...the higher the better.
I have a friend that just bought a cheap set of HID headlights and he said it was the best thing he has ever done to his truck. He says they are amazing and well worth the money! Im waiting for my current bulbs to burn out and then I will be switching to HID as well.