Ok this time from a suggestion a decided to make the poll either helmet mount or handlebar mount.
Thanks again.

Like everyone others are saying on the other survey, both would be ideal but too expensive.

With a choice of one light, most mountain bikers will use a headlamp. This is because you have to "paint" the curves and switchbacks of the trail far enough ahead to determine your line. This kind of precise, smooth pointing can't be done with a handlebar mount for obvious reasons. But most of the time, the area in front of your wheel is dark and you are navigating from short-term memory. As you go faster, you point it further down the trail but in slow, technical spots, you point it directly in front of you.

With the addition of a handlebar light, textures and tread really stand-out because the source is below your eye-line. It alleviates some anxiety because you can verify what you were seeing a half-second earlier by keeping the dark spot in front of your tire illuminated.

I have both. Total cost for my system is about 250.00

I use both. If I had to choose just one, it would be the helmet. I've got about $200 in my full setup.

I have a handlebar mount only and i'll say that it's pretty terrible, i need to find a way to rig it up to the helmet,

i think its a niterider trailrat (on sale last year), anyone know off the top of their head if NR makes a helmet mount conversion (i could probably look this up pretty easily but i was already replying), i could probably figure out how to get it attached to the helmet but i know that i would need a longer cord as well and i would guess i'm not the first one with this issue.

A couple of years ago I bought my first light, a 15W Halogen, that came with the bar mount. First ride I figured out that that was not going to work on the trail. I ordered the helmet mount kit and it worked great.

I currently have a Trinewt LED light - very bright and have never even tried the bar mount. It works great on the helmet, I can see everything I need to see.

I do have a $15 cheap LED light on the bar for a backup and it clips off for use as a flashlight (very light and I rarely use it). It is always a good idea to have some type of backup in case something goes wrong with your light. I also carry a small backpacking headlamp in my camelback as a second backup. The backup can also be used around the car before and after the ride when you are not wearing the helmet/camelback with the battery.

Both is best. For just one helmet mounted is prefered because it tracks your head/eye movement but a bar mount, not being in your line of sight, produces shadows and may make things on the trail easier to see. Helmet lights tend to "wash out" the details. I use both. Started years ago with Niterider halogens but now use HIDs.
They say I look like a freight train coming through the woods.

I voted "on helmet." At this point that's all b/c of cost. At some point, I might get a second light for the bars though. I can see the advantage of having both.

I use both also. My bar mount light is a Niterider Minewt (100.00 and very bright). My helmet light is a Niterider Moab light.

Brian

I have one on my helmet. After one ride - I liked it.

However, the wife hated the idea of riding at night once she started riding the trails during the day.

When or if my friends will night ride I'll get two for the bar.

$80 "900" lumen MagicShine for the bars from GeoMan
$75 230 lumen 4Sevens Quark Turbo for the helmet

This combo lights up Blankets like its daylight. Loads of fun.

-Tom