H'bar bags that don't obstruct a bar-mounted headlight, but still have a map case are going to be tough to come by. You might consider getting a h'bar mounted water bottle cage for the battery, and just using a clip-on map case for holding route sheets.
I have the large Topeak Tourguide DX bag. I love the map pocket and it is roomy enough that I can take a fully days food with me to work when I take it on the road bike.
As far as light mount goes, that is the only down side. There is a little folder that slides on the bag mount that is great to use for a bike computer, but it is far to low to allow a headlight to shine over the bag. In my case I use a B&M DLumotec light running off the generator hub so having the light mounts on the fork works well as it keeps the wiring short. There are some adapters that allow you to mount lights elsewhere, but is does get a bit tricky. Even so, I love the handlebar bag. I jokingly call it my "man purse."
If I need to go into a store I just pop the bag off, and anything of real value therefore comes with me into the store.
Thanks for everyone's input.
It's just hard to believe that in this day and age with advances in bicycle lighting (I'm just getting back into bicycling after a hiatus since the 80's) that no company has produced a handlebar bag with a map pocket that won't obstruct a headlight.
I think I'll go with the Viewpoint Spacebar and the Twofish Lockblocks as detailed in varuscelli's thread; it seems to be quite the setup, even though I've already dropped some coin on a Cygolite Hi-flux 200. Oh well, live and learn. I'm just happy I've found this forum.