While I use Niterider HID's for mountain biking (handlebar and helmet), their roadrat and trailrat models ($100 - $120) are excellent for biking around town or on well maintained beginner - intermediate trails. For biking two or three times a week for less than 3 hours per ride, these are excellent. I use the trailrat myself for these purposes.
The beam is powerful (not compared to the HIDs) and very useful. The features these lights lack compared to more explensive models include a smart charger, lithium ion battery, multiple light output levels, and HID technology. So long as you don't mind up to 8 hour charge times and are conscious of the risk of overcharging due to the lack of having smartcharging technology the trailrat (and I'm sure the roadrat) are great investments. They may cost a bit more up front, but their usefullness will far outweigh the $50 cateye LEDs.
My opinion is that there is no such thing as a "being seen" bike light. There are obstacles during night biking even when there is ambient light present. If you plan to maintain these lights, they will reward you far beyond the $120 investment.
Finally, mount these to the handlebar. There is no better to place your mount your powerful light. You can get one of the cateye LEDs for helmet mount (to check gears, bike computer, and most importantly for better visibility when turning). I am in a hurry, have to go out, so I am being brief. I hope this is helpful, let me know if you want anymore info on my setup.
p.s. I used the twofish flashlight mount before I picked up the trailrat (for regular biking). It's a great little mount but flashlights aren't designed to be bike lights (high battery cost and/or low comparative runtime at high output). I think it's a neat gadget to toss in your pack for emergency mount (better than duct tape), but get yourself a dedicated bike light. If you do ever use the twofish mount, make sure you mount the flashlight down; a lot of people mount the flashlight up and complain about the light shifting on rough terain.
Also, here is an older thread on handlebar flashlight mounts:
http://www.candlepowerforums.com/vb/showthread.php?t=79435