Tygab, Minuora(sp) make a something called a space bar. It's t-bar shape thing that attaches to your bars to give more "real Estate."
I have two Sigma LED's on my cannondale, and Rechargeable Cygolite on my Friday. The Cygolight is brighter, but is much more expensive, and has less run time(about 3/4 of an hour on bright). The best solution to have both bar and helmet mounted lights, but that would depend on what you're doing (riding Brevet all night vs the club ride ran a little late) The more reflectivity/light you can manage, the better!