http://www.cygolite.com/2-Products/18-TridenX-LiIon.htm
Been reading good things about this light, about $300. Cygo has been around a while and has a good rep.

Also, the Exposure Race Maxx, $350, maybe tempting to you.
http://www.exposurelightsusa.com/
Exposure has been around a while and has a rabid cult-like following. I am considering 2 of these myself.

Personally, I am now a huge fan of dual light heads. I ran a single hi-po bulb (25 watt) for a long time and recently switched to dual LED flashlights. About the same brightness but MUCH more respect from traffic. fwiw.

the DiNotte 200L Dual gets good press as well but I understand they are not a "spot", more of a uniform, even lighting. Personally i like a light with more "throw" down the road so I can see hazards in the road @ hi speed better. You say you have one good downhill - with the right light you should be able to hit daylight speeds safely.