Boy...it feels like someone is trying to step on my toes!! /ubbthreads/images/graemlins/poke2.gif /ubbthreads/images/graemlins/crackup.gif
Seriously though. Most get a 5W for the beam pattern. A wide beam pattern that is. It will put lots of light on the subject at the expense of throw. The problem with the 5W is the heat it generates and the runtime, or lack thereof.
If you get a decent bin 5W, say at least a V flux, you really don't need to drive the hell out of it to have a useful light. I actually have an A3 with an unspecified bin 5W and a BB500 light engine. This is a very useful light. Out to medium ranges, it has good throw and you can SEE what you are shining the light on because there is so much light. The heat from this combination is negligible. The light never gets more than warm. If you go to 700mA, you'll get more light at the expense of heat and runtime.
Just remember that the biggest and brightest is not always the best tool for the job. You should assess your needs and build accordingly.
Now, just some food for thought. If you are looking for a wider beam with reasonable throw, the Aleph II with a nice Lux III running at about 667mA is a very nice light and a good bit smaller than the A3 head. It also runs for a good long time on 2X123s.
If you're interested, I think I have a V3U emitter laying around on my bench someplace.