Best: If you want the brightest, I suggest retrofit your headlamps to use the much talked about Acura TSX projector assembly and lighting system, used by lots of people on lots of different cars, because of the best beam pattern and light output. It's really about the reflectors and lenses more than the bulbs themselves.
Excellent: Next best option would be a set of E46 stock xenons, since they are almost as commonly used as the TSX projectors, and are really quite nice.
Very Good: Third option, I would get the Depo headlight assembly with the projectors and 55watt or 35 watt HID system. The 55 watt system is supposed to be a little brighter than the 35 watt system, but stock HIDs are 35 watt and 35 watts has been bright enough for me. Once again, it's more about the projector setup than the bulbs when you are using HID.