I've got a Blackburn Mars 3.0 on the seatpost, a Bell 0.5 watt butterfly light on the left chain stay, and a PDW Tailbot on the rear fender. I can move the Blackburn from the SP to my rack bag when I use the bag.
I looked at he Cateye Rapid 3 last time I was at LBS, but I think I'll wait till I can get a Radbot to replace the Blackburn.
If you want side illumination check these out, I'm thinking about it; http://www.monkeylectric.com/m132s.htm

There is a light hacking forum somewhere, I forget what it's called and i didn't earmark it, but there was a lot of good info there.
It's not the wattage that counts, it's the lumens.