I prefer the challenge of 'rolling my own' circuit, and have had sucess with the Linear Tech
LTC3425 and
LTC3428 , as well as the Texas Instruments
TPS61020. There are many other choices from these and other manufacturers. None of these are easy or quick to develop without circuit boards and SMD soldering skils.
Fortunately, there are many pre-made converter boards available. Check at
TaskLed,
Lambda and
Sandwich Shoppe among others.
Search around the forums including BST, you'll find many choices.
Anyone else care to recomend a favorite?
Crux