I've got a Light and Motion Stella 200L for the front. It's pretty lightweight, easy to mount, and the battery runs for 5 hours on high (200 Lumens). That being said, it's going to eventually be mounted to my helmet, and I might get a Dinotte 400l, Minewt Dual, or a Trinewt for the bars.
There is no reason that you shouldn't have a Superflash (or two) in the back. I've got one on my bag, one on my bike.