I would lean toward Turbocat for the best halogen system around $200, specifically the S15 or S25 model (see link):

http://www.turbocatusa.com/config.html

Marwi is also good in that price range:

http://www.pricepoint.com/detail/162...=20&zmap=16258

http://www.blueskycycling.com/view_product.php?pid=2788

http://www.bikesomewhere.com/bikesom...bestbikebuys=1

Edit: Forgot one more, Light and Motion Solo Logic:

http://www.nashbar.com/profile.cfm?sku=15862