If you want a inexpensive self contained battery type of light then look at the Cateye brand of LED lights, they are adequate for the price; especially the LD500 and 600.

However your going to spend nearly as much for one of those as a Cygolite Metro that cost $48 and is a dual beam 13watt total halogen light that will be WAY brighter then any LED on the market. And the Metro uses 6 D batteries that are in a pouch that attaches to the frame via a velcro strap so your water bottle cages are not used. You can use either throwaway or rechargeable bats with the Metro; the bats will last for 5 hours on low and 2.5 hours on high. ]

I have the Metro and use to have the Cateye el500 and I can tell you that even with just on beam on the Metro was far far brighter the the Cateye.